diff --git a/src/Bundle/ChillCalendarBundle/Entity/Calendar.php b/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
index ab50e7a8a..2a05c1c77 100644
--- a/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
+++ b/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
@@ -12,7 +12,6 @@ declare(strict_types=1);
 namespace Chill\CalendarBundle\Entity;
 
 use Chill\ActivityBundle\Entity\Activity;
-use Chill\CalendarBundle\Repository\CalendarRepository;
 use Chill\MainBundle\Doctrine\Model\TrackCreationInterface;
 use Chill\MainBundle\Doctrine\Model\TrackCreationTrait;
 use Chill\MainBundle\Doctrine\Model\TrackUpdateInterface;
@@ -38,7 +37,7 @@ use function in_array;
 
 /**
  * @ORM\Table(name="chill_calendar.calendar", indexes={@ORM\Index(name="idx_calendar_remote", columns={"remoteId"})}))
- * @ORM\Entity(repositoryClass=CalendarRepository::class)
+ * @ORM\Entity
  */
 class Calendar implements TrackCreationInterface, TrackUpdateInterface
 {
@@ -54,6 +53,24 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
 
     public const STATUS_VALID = 'valid';
 
+    /**
+     * a list of invite which have been added during this session.
+     *
+     * @var array|Invite[]
+     */
+    public array $newInvites = [];
+
+    /**
+     * a list of invite which have been removed during this session.
+     *
+     * @var array|Invite[]
+     */
+    public array $oldInvites = [];
+
+    public ?CalendarRange $previousCalendarRange = null;
+
+    public ?User $previousMainUser = null;
+
     /**
      * @ORM\ManyToOne(targetEntity="Chill\PersonBundle\Entity\AccompanyingPeriod")
      * @Serializer\Groups({"read"})
@@ -118,7 +135,7 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
      * @ORM\ManyToOne(targetEntity="Chill\MainBundle\Entity\User")
      * @Serializer\Groups({"calendar:read", "read"})
      */
-    private ?User $mainUser;
+    private ?User $mainUser = null;
 
     /**
      * @ORM\ManyToMany(
@@ -162,6 +179,9 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
         $this->invites = new ArrayCollection();
     }
 
+    /**
+     * @internal Use {@link (Calendar::addUser)} instead
+     */
     public function addInvite(Invite $invite): self
     {
         if ($invite->getCalendar() instanceof Calendar && $invite->getCalendar() !== $this) {
@@ -169,6 +189,8 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
         }
 
         $this->invites[] = $invite;
+        $this->newInvites[] = $invite;
+
         $invite->setCalendar($this);
 
         return $this;
@@ -338,6 +360,11 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
         return $this->getInvites()->map(static function (Invite $i) { return $i->getUser(); });
     }
 
+    public function hasCalendarRange(): bool
+    {
+        return null !== $this->calendarRange;
+    }
+
     public static function loadValidatorMetadata(ClassMetadata $metadata): void
     {
         $metadata->addPropertyConstraint('startDate', new NotBlank());
@@ -352,10 +379,14 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
         ]));
     }
 
+    /**
+     * @internal Use {@link (Calendar::removeUser)} instead
+     */
     public function removeInvite(Invite $invite): self
     {
         if ($this->invites->removeElement($invite)) {
             $invite->setCalendar(null);
+            $this->oldInvites[] = $invite;
         }
 
         return $this;
@@ -405,8 +436,15 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
 
     public function setCalendarRange(?CalendarRange $calendarRange): self
     {
-        $this->calendarRange = $calendarRange;
+        if ($this->calendarRange !== $calendarRange) {
+            $this->previousCalendarRange = $this->calendarRange;
 
+            if (null !== $this->previousCalendarRange) {
+                $this->previousCalendarRange->setCalendar(null);
+            }
+        }
+
+        $this->calendarRange = $calendarRange;
         $this->calendarRange->setCalendar($this);
 
         return $this;
@@ -442,6 +480,10 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
 
     public function setMainUser(?User $mainUser): self
     {
+        if ($this->mainUser !== $mainUser) {
+            $this->previousMainUser = $this->mainUser;
+        }
+
         $this->mainUser = $mainUser;
 
         return $this;
diff --git a/src/Bundle/ChillCalendarBundle/Entity/CalendarRange.php b/src/Bundle/ChillCalendarBundle/Entity/CalendarRange.php
index 25ae0a3e8..ea1035340 100644
--- a/src/Bundle/ChillCalendarBundle/Entity/CalendarRange.php
+++ b/src/Bundle/ChillCalendarBundle/Entity/CalendarRange.php
@@ -93,7 +93,7 @@ class CalendarRange implements TrackCreationInterface, TrackUpdateInterface
     /**
      * @internal use {@link (Calendar::setCalendarRange)} instead
      */
-    public function setCalendar(Calendar $calendar): void
+    public function setCalendar(?Calendar $calendar): void
     {
         $this->calendar = $calendar;
     }
diff --git a/src/Bundle/ChillCalendarBundle/Entity/Invite.php b/src/Bundle/ChillCalendarBundle/Entity/Invite.php
index 7abd4f2c2..751727af8 100644
--- a/src/Bundle/ChillCalendarBundle/Entity/Invite.php
+++ b/src/Bundle/ChillCalendarBundle/Entity/Invite.php
@@ -11,7 +11,6 @@ declare(strict_types=1);
 
 namespace Chill\CalendarBundle\Entity;
 
-use Chill\CalendarBundle\Repository\InviteRepository;
 use Chill\MainBundle\Doctrine\Model\TrackCreationInterface;
 use Chill\MainBundle\Doctrine\Model\TrackCreationTrait;
 use Chill\MainBundle\Doctrine\Model\TrackUpdateInterface;
@@ -23,7 +22,7 @@ use Symfony\Component\Serializer\Annotation as Serializer;
 
 /**
  * @ORM\Table(name="chill_calendar.invite")
- * @ORM\Entity(repositoryClass=InviteRepository::class)
+ * @ORM\Entity
  */
 class Invite implements TrackUpdateInterface, TrackCreationInterface
 {
diff --git a/src/Bundle/ChillCalendarBundle/Messenger/Handler/CalendarToRemoteHandler.php b/src/Bundle/ChillCalendarBundle/Messenger/Handler/CalendarToRemoteHandler.php
index c71f2deaf..ff4083e4a 100644
--- a/src/Bundle/ChillCalendarBundle/Messenger/Handler/CalendarToRemoteHandler.php
+++ b/src/Bundle/ChillCalendarBundle/Messenger/Handler/CalendarToRemoteHandler.php
@@ -11,8 +11,13 @@ declare(strict_types=1);
 
 namespace Chill\CalendarBundle\Messenger\Handler;
 
+use Chill\CalendarBundle\Entity\Invite;
 use Chill\CalendarBundle\Messenger\Message\CalendarMessage;
 use Chill\CalendarBundle\RemoteCalendar\Connector\RemoteCalendarConnectorInterface;
+use Chill\CalendarBundle\Repository\CalendarRangeRepository;
+use Chill\CalendarBundle\Repository\CalendarRepository;
+use Chill\CalendarBundle\Repository\InviteRepository;
+use Chill\MainBundle\Repository\UserRepository;
 use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Component\Messenger\Attribute\AsMessageHandler;
 use Symfony\Component\Messenger\Handler\MessageHandlerInterface;
@@ -24,9 +29,63 @@ class CalendarToRemoteHandler implements MessageHandlerInterface
 {
     private RemoteCalendarConnectorInterface $calendarConnector;
 
-    private EntityManagerInterface $em;
+    private CalendarRangeRepository $calendarRangeRepository;
+
+    private CalendarRepository $calendarRepository;
+
+    private EntityManagerInterface $entityManager;
+
+    private InviteRepository $inviteRepository;
+
+    private UserRepository $userRepository;
+
+    public function __construct(
+        CalendarRangeRepository $calendarRangeRepository,
+        CalendarRepository $calendarRepository,
+        EntityManagerInterface $entityManager,
+        InviteRepository $inviteRepository,
+        RemoteCalendarConnectorInterface $calendarConnector,
+        UserRepository $userRepository
+    ) {
+        $this->calendarConnector = $calendarConnector;
+        $this->calendarRepository = $calendarRepository;
+        $this->calendarRangeRepository = $calendarRangeRepository;
+        $this->entityManager = $entityManager;
+        $this->userRepository = $userRepository;
+        $this->inviteRepository = $inviteRepository;
+    }
 
     public function __invoke(CalendarMessage $calendarMessage)
     {
+        $calendar = $this->calendarRepository->find($calendarMessage->getCalendarId());
+
+        if (null !== $calendarMessage->getPreviousCalendarRangeId()) {
+            $previousCalendarRange = $this->calendarRangeRepository
+                ->find($calendarMessage->getPreviousCalendarRangeId());
+        }
+
+        if (null !== $calendarMessage->getPreviousMainUserId()) {
+            $previousMainUser = $this->userRepository
+                ->find($calendarMessage->getPreviousMainUserId());
+        }
+        $newInvites = array_filter(
+            array_map(
+                function ($id) { return $this->inviteRepository->find($id); },
+                $calendarMessage->getNewInvitesIds(),
+            ),
+            static function (?Invite $invite) { return null !== $invite; }
+        );
+
+        $this->calendarConnector->syncCalendar(
+            $calendar,
+            $calendarMessage->getAction(),
+            $previousCalendarRange ?? null,
+            $previousMainUser ?? null,
+            $calendarMessage->getOldInvites(),
+            $newInvites
+        );
+
+        $calendar->preventEnqueueChanges = true;
+        $this->entityManager->flush();
     }
 }
diff --git a/src/Bundle/ChillCalendarBundle/Messenger/Message/CalendarMessage.php b/src/Bundle/ChillCalendarBundle/Messenger/Message/CalendarMessage.php
index b6860249a..44af1e6a7 100644
--- a/src/Bundle/ChillCalendarBundle/Messenger/Message/CalendarMessage.php
+++ b/src/Bundle/ChillCalendarBundle/Messenger/Message/CalendarMessage.php
@@ -12,6 +12,7 @@ declare(strict_types=1);
 namespace Chill\CalendarBundle\Messenger\Message;
 
 use Chill\CalendarBundle\Entity\Calendar;
+use Chill\CalendarBundle\Entity\Invite;
 use Chill\MainBundle\Entity\User;
 
 class CalendarMessage
@@ -26,11 +27,38 @@ class CalendarMessage
 
     private int $calendarId;
 
-    public function __construct(Calendar $calendar, string $action, User $byUser)
-    {
+    private array $newInvitesIds = [];
+
+    /**
+     * @var array<array{inviteId: int, userId: int, userEmail: int, userLabel: string}>
+     */
+    private array $oldInvites = [];
+
+    private ?int $previousCalendarRangeId = null;
+
+    private ?int $previousMainUserId = null;
+
+    public function __construct(
+        Calendar $calendar,
+        string $action,
+        User $byUser
+    ) {
         $this->calendarId = $calendar->getId();
         $this->byUserId = $byUser->getId();
         $this->action = $action;
+        $this->previousCalendarRangeId = null !== $calendar->previousCalendarRange ?
+            $calendar->previousCalendarRange->getId() : null;
+        $this->previousMainUserId = null !== $calendar->previousMainUser ?
+            $calendar->previousMainUser->getId() : null;
+        $this->newInvitesIds = array_map(static fn (Invite $i) => $i->getId(), $calendar->newInvites);
+        $this->oldInvites = array_map(static function (Invite $i) {
+            return [
+                'inviteId' => $i->getId(),
+                'userId' => $i->getUser()->getId(),
+                'userEmail' => $i->getUser()->getEmail(),
+                'userLabel' => $i->getUser()->getLabel(),
+            ];
+        }, $calendar->oldInvites);
     }
 
     public function getAction(): string
@@ -47,4 +75,30 @@ class CalendarMessage
     {
         return $this->calendarId;
     }
+
+    /**
+     * @return array|int[]|null[]
+     */
+    public function getNewInvitesIds(): array
+    {
+        return $this->newInvitesIds;
+    }
+
+    /**
+     * @return array<array{inviteId: int, userId: int, userEmail: int, userLabel: string}>
+     */
+    public function getOldInvites(): array
+    {
+        return $this->oldInvites;
+    }
+
+    public function getPreviousCalendarRangeId(): ?int
+    {
+        return $this->previousCalendarRangeId;
+    }
+
+    public function getPreviousMainUserId(): ?int
+    {
+        return $this->previousMainUserId;
+    }
 }
diff --git a/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraph/RemoteEventConverter.php b/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraph/RemoteEventConverter.php
index 569ec2f56..f5dce2074 100644
--- a/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraph/RemoteEventConverter.php
+++ b/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraph/RemoteEventConverter.php
@@ -11,8 +11,12 @@ declare(strict_types=1);
 
 namespace Chill\CalendarBundle\RemoteCalendar\Connector\MSGraph;
 
+use Chill\CalendarBundle\Entity\Calendar;
 use Chill\CalendarBundle\Entity\CalendarRange;
+use Chill\CalendarBundle\Entity\Invite;
 use Chill\CalendarBundle\RemoteCalendar\Model\RemoteEvent;
+use Chill\PersonBundle\Entity\Person;
+use Chill\PersonBundle\Templating\Entity\PersonRenderInterface;
 use DateTimeImmutable;
 use DateTimeZone;
 use Symfony\Contracts\Translation\TranslatorInterface;
@@ -29,13 +33,16 @@ class RemoteEventConverter
 
     private DateTimeZone $defaultDateTimeZone;
 
+    private PersonRenderInterface $personRender;
+
     private DateTimeZone $remoteDateTimeZone;
 
     private TranslatorInterface $translator;
 
-    public function __construct(TranslatorInterface $translator)
+    public function __construct(PersonRenderInterface $personRender, TranslatorInterface $translator)
     {
         $this->translator = $translator;
+        $this->personRender = $personRender;
         $this->defaultDateTimeZone = (new DateTimeImmutable())->getTimezone();
         $this->remoteDateTimeZone = self::getRemoteTimeZone();
     }
@@ -71,6 +78,42 @@ class RemoteEventConverter
         ];
     }
 
+    public function calendarToEvent(Calendar $calendar): array
+    {
+        return [
+            'subject' => '[Chill] ' .
+                implode(
+                    ', ',
+                    $calendar->getPersons()->map(function (Person $p) {
+                        return $this->personRender->renderString($p, []);
+                    })->toArray()
+                ),
+            'start' => [
+                'dateTime' => $calendar->getStartDate()->setTimezone($this->remoteDateTimeZone)
+                    ->format(self::REMOTE_DATE_FORMAT),
+                'timeZone' => 'UTC',
+            ],
+            'end' => [
+                'dateTime' => $calendar->getEndDate()->setTimezone($this->remoteDateTimeZone)
+                    ->format(self::REMOTE_DATE_FORMAT),
+                'timeZone' => 'UTC',
+            ],
+            'allowNewTimeProposals' => false,
+            'attendees' => $calendar->getInvites()->map(
+                static function (Invite $i) {
+                        return [
+                            'emailAddress' => [
+                                'address' => $i->getUser()->getEmail(),
+                                'name' => $i->getUser()->getLabel(),
+                            ],
+                            'type' => 'Required',
+                        ];
+                    }
+            )->toArray(),
+            'transactionId' => 'calendar_' . $calendar->getId(),
+        ];
+    }
+
     public function convertAvailabilityToRemoteEvent(array $event): RemoteEvent
     {
         $startDate =
diff --git a/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraphRemoteCalendarConnector.php b/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraphRemoteCalendarConnector.php
index 513b2f66f..b38dc6491 100644
--- a/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraphRemoteCalendarConnector.php
+++ b/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/MSGraphRemoteCalendarConnector.php
@@ -21,6 +21,7 @@ use Chill\CalendarBundle\RemoteCalendar\Connector\MSGraph\RemoteEventConverter;
 use Chill\CalendarBundle\Repository\CalendarRangeRepository;
 use Chill\MainBundle\Entity\User;
 use DateTimeImmutable;
+use Exception;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 use Symfony\Component\HttpFoundation\Response;
@@ -137,9 +138,45 @@ class MSGraphRemoteCalendarConnector implements RemoteCalendarConnectorInterface
         $this->removeEvent($remoteId, $user);
     }
 
-    public function syncCalendar(Calendar $calendar, string $action): void
+    public function syncCalendar(Calendar $calendar, string $action, ?CalendarRange $previousCalendarRange, ?User $previousMainUser, ?array $oldInvites, ?array $newInvites): void
     {
-        // TODO: Implement syncCalendar() method.
+        /*
+         * cases to support:
+         *
+         * * a calendar range is created:
+         *     * create on remote
+         *     * if calendar range is associated: remove the range
+         * * a Calendar change the CalendarRange:
+         *     * re-create the previous calendar range;
+         *     * remove the current calendar range
+         * * a calendar change the mainUser
+         *     * cancel the calendar in the previous mainUser
+         *     * recreate the previous calendar range in the previousMainUser, if any
+         *     * delete the current calendar range in the current mainUser, if any
+         *     * create the calendar in the current mainUser
+         *
+         */
+
+        if (!$calendar->hasRemoteId()) {
+            $this->createCalendarOnRemote($calendar);
+        } else {
+            if (null !== $previousMainUser) {
+                // cancel event in previousMainUserCalendar
+                // CREATE event in currentMainUser
+            }
+            // PATCH event in currentMainUer
+        }
+
+        if ($calendar->hasCalendarRange() && $calendar->getCalendarRange()->hasRemoteId()) {
+            $this->removeEvent(
+                $calendar->getCalendarRange()->getRemoteId(),
+                $calendar->getCalendarRange()->getUser()
+            );
+        }
+
+        if (null !== $previousCalendarRange) {
+            // create previousCalendarRange
+        }
     }
 
     public function syncCalendarRange(CalendarRange $calendarRange): void
@@ -151,6 +188,72 @@ class MSGraphRemoteCalendarConnector implements RemoteCalendarConnectorInterface
         }
     }
 
+    private function createCalendarOnRemote(Calendar $calendar): void
+    {
+        $eventData = $this->remoteEventConverter->calendarToEvent($calendar);
+
+        [
+            'id' => $id,
+            'lastModifiedDateTime' => $lastModified,
+            'changeKey' => $changeKey
+        ] = $this->createOnRemote($eventData, $calendar->getMainUser(), 'calendar_' . $calendar->getId());
+
+        if (null === $id) {
+            return;
+        }
+
+        $calendar
+            ->setRemoteId($id)
+            ->addRemoteAttributes([
+                'lastModifiedDateTime' => $lastModified,
+                'changeKey' => $changeKey,
+            ]);
+    }
+
+    /**
+     * @param string $identifier an identifier for logging in case of something does not work
+     *
+     * @return array{?id: string, ?lastModifiedDateTime: int, ?changeKey: string}
+     */
+    private function createOnRemote(array $eventData, User $user, string $identifier): array
+    {
+        $userId = $this->mapCalendarToUser->getUserId($user);
+
+        if (null === $userId) {
+            $this->logger->warning('user does not have userId nor calendarId', [
+                'user_id' => $user->getId(),
+                'calendar_identifier' => $identifier,
+            ]);
+
+            return [];
+        }
+        dump($eventData);
+
+        try {
+            $event = $this->machineHttpClient->request(
+                'POST',
+                'users/' . $userId . '/calendar/events',
+                [
+                    'json' => $eventData,
+                ]
+            )->toArray();
+        } catch (ClientExceptionInterface $e) {
+            $this->logger->warning('could not save calendar range to remote', [
+                'exception' => $e->getTraceAsString(),
+                'content' => $e->getResponse()->getContent(),
+                'calendar_identifier' => $identifier,
+            ]);
+
+            throw $e;
+        }
+
+        return [
+            'id' => $event['id'],
+            'lastModifiedDateTime' => $this->remoteEventConverter->getLastModifiedDate($event)->getTimestamp(),
+            'changeKey' => $event['changeKey'],
+        ];
+    }
+
     private function createRemoteCalendarRange(CalendarRange $calendarRange): void
     {
         $userId = $this->mapCalendarToUser->getUserId($calendarRange->getUser());
@@ -191,6 +294,31 @@ class MSGraphRemoteCalendarConnector implements RemoteCalendarConnectorInterface
             ]);
     }
 
+    private function getOnRemote(User $user, string $remoteId): array
+    {
+        $userId = $this->mapCalendarToUser->getUserId($user);
+
+        if (null === $userId) {
+            throw new Exception('no remote calendar for this user', [
+                'user' => $user->getId(),
+                'remoteId' => $remoteId,
+            ]);
+        }
+
+        try {
+            return $this->machineHttpClient->request(
+                'GET',
+                'users/' . $userId . '/calendar/events/' . $remoteId
+            )->toArray();
+        } catch (ClientExceptionInterface $e) {
+            $this->logger->warning('Could not get event from calendar', [
+                'remoteId' => $remoteId,
+            ]);
+
+            throw $e;
+        }
+    }
+
     private function getScheduleTimesForUser(User $user, DateTimeImmutable $startDate, DateTimeImmutable $endDate): array
     {
         $userId = $this->mapCalendarToUser->getUserId($user);
@@ -236,6 +364,48 @@ class MSGraphRemoteCalendarConnector implements RemoteCalendarConnectorInterface
         );
     }
 
+    /**
+     * @param string $identifier an identifier for logging in case of something does not work
+     *
+     * @return array{?id: string, ?lastModifiedDateTime: int, ?changeKey: string}
+     */
+    private function patchOnRemote(string $remoteId, array $eventData, User $user, string $identifier): array
+    {
+        $userId = $this->mapCalendarToUser->getUserId($user);
+
+        if (null === $userId) {
+            $this->logger->warning('user does not have userId nor calendarId', [
+                'user_id' => $user->getId(),
+                'calendar_identifier' => $identifier,
+            ]);
+
+            return [];
+        }
+
+        try {
+            $event = $this->machineHttpClient->request(
+                'PATCH',
+                'users/' . $userId . '/calendar/events/' . $remoteId,
+                [
+                    'json' => $eventData,
+                ]
+            )->toArray();
+        } catch (ClientExceptionInterface $e) {
+            $this->logger->warning('could not update calendar range to remote', [
+                'exception' => $e->getTraceAsString(),
+                'calendarRangeId' => $identifier,
+            ]);
+
+            throw $e;
+        }
+
+        return [
+            'id' => $event['id'],
+            'lastModifiedDateTime' => $this->remoteEventConverter->getLastModifiedDate($event)->getTimestamp(),
+            'changeKey' => $event['changeKey'],
+        ];
+    }
+
     private function removeEvent($remoteId, User $user): void
     {
         $userId = $this->mapCalendarToUser->getUserId($user);
diff --git a/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/NullRemoteCalendarConnector.php b/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/NullRemoteCalendarConnector.php
index 774d086ff..ef0db2548 100644
--- a/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/NullRemoteCalendarConnector.php
+++ b/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/NullRemoteCalendarConnector.php
@@ -39,7 +39,7 @@ class NullRemoteCalendarConnector implements RemoteCalendarConnectorInterface
     {
     }
 
-    public function syncCalendar(Calendar $calendar, string $action): void
+    public function syncCalendar(Calendar $calendar, string $action, ?CalendarRange $previousCalendarRange, ?User $previousMainUser, ?array $oldInvites, ?array $newInvites): void
     {
     }
 
diff --git a/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/RemoteCalendarConnectorInterface.php b/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/RemoteCalendarConnectorInterface.php
index 358633141..c55c06f86 100644
--- a/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/RemoteCalendarConnectorInterface.php
+++ b/src/Bundle/ChillCalendarBundle/RemoteCalendar/Connector/RemoteCalendarConnectorInterface.php
@@ -40,7 +40,10 @@ interface RemoteCalendarConnectorInterface
 
     public function removeCalendarRange(string $remoteId, array $remoteAttributes, User $user): void;
 
-    public function syncCalendar(Calendar $calendar, string $action): void;
+    /**
+     * @param array<array{inviteId: int, userId: int, userEmail: int, userLabel: string}> $oldInvites
+     */
+    public function syncCalendar(Calendar $calendar, string $action, ?CalendarRange $previousCalendarRange, ?User $previousMainUser, ?array $oldInvites, ?array $newInvites): void;
 
     public function syncCalendarRange(CalendarRange $calendarRange): void;
 }
diff --git a/src/Bundle/ChillCalendarBundle/Repository/CalendarRangeRepository.php b/src/Bundle/ChillCalendarBundle/Repository/CalendarRangeRepository.php
index 34dcf136d..ae30ab397 100644
--- a/src/Bundle/ChillCalendarBundle/Repository/CalendarRangeRepository.php
+++ b/src/Bundle/ChillCalendarBundle/Repository/CalendarRangeRepository.php
@@ -150,13 +150,15 @@ class CalendarRangeRepository implements ObjectRepository
     {
         $qb = $this->repository->createQueryBuilder('cr');
 
+        $qb->leftJoin('cr.calendar', 'calendar');
+
         return $qb
             ->where(
                 $qb->expr()->andX(
                     $qb->expr()->eq('cr.user', ':user'),
                     $qb->expr()->gte('cr.startDate', ':startDate'),
                     $qb->expr()->lte('cr.endDate', ':endDate'),
-                    $qb->expr()->eq(0, 'SIZE(cr.calendars)')
+                    $qb->expr()->isNull('calendar')
                 )
             )
             ->setParameters([
diff --git a/src/Bundle/ChillCalendarBundle/Repository/CalendarRepository.php b/src/Bundle/ChillCalendarBundle/Repository/CalendarRepository.php
index 55fba5f80..74d8c8ddb 100644
--- a/src/Bundle/ChillCalendarBundle/Repository/CalendarRepository.php
+++ b/src/Bundle/ChillCalendarBundle/Repository/CalendarRepository.php
@@ -12,52 +12,68 @@ declare(strict_types=1);
 namespace Chill\CalendarBundle\Repository;
 
 use Chill\CalendarBundle\Entity\Calendar;
-use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Chill\PersonBundle\Entity\AccompanyingPeriod;
+use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\EntityRepository;
-use Doctrine\Persistence\ManagerRegistry;
+use Doctrine\Persistence\ObjectRepository;
 
-/**
- * @method Calendar|null find($id, $lockMode = null, $lockVersion = null)
- * @method Calendar|null findOneBy(array $criteria, array $orderBy = null)
- * @method Calendar[]    findAll()
- * @method Calendar[]    findBy(array $criteria, array $orderBy = null, $limit = null, $offset = null)
- */
-class CalendarRepository extends ServiceEntityRepository
+class CalendarRepository implements ObjectRepository
 {
-    // private EntityRepository $repository;
+    private EntityRepository $repository;
 
-    public function __construct(ManagerRegistry $registry)
+    public function __construct(EntityManagerInterface $entityManager)
     {
-        parent::__construct($registry, Calendar::class);
-        // $this->repository = $entityManager->getRepository(AccompanyingPeriodWork::class);
+        $this->repository = $entityManager->getRepository(Calendar::class);
     }
 
-    // /**
-    //  * @return Calendar[] Returns an array of Calendar objects
-    //  */
-    /*
-    public function findByExampleField($value)
+    public function countByAccompanyingPeriod(AccompanyingPeriod $period): int
     {
-        return $this->createQueryBuilder('c')
-            ->andWhere('c.exampleField = :val')
-            ->setParameter('val', $value)
-            ->orderBy('c.id', 'ASC')
-            ->setMaxResults(10)
-            ->getQuery()
-            ->getResult()
-        ;
+        return $this->repository->count(['accompanyingPeriod' => $period]);
     }
+
+    public function find($id): ?Calendar
+    {
+        return $this->repository->find($id);
+    }
+
+    /**
+     * @return array|Calendar[]
      */
-
-    /*
-    public function findOneBySomeField($value): ?Calendar
+    public function findAll(): array
     {
-        return $this->createQueryBuilder('c')
-            ->andWhere('c.exampleField = :val')
-            ->setParameter('val', $value)
-            ->getQuery()
-            ->getOneOrNullResult()
-        ;
+        return $this->repository->findAll();
     }
+
+    /**
+     * @return array|Calendar[]
      */
+    public function findBy(array $criteria, ?array $orderBy = null, ?int $limit = null, ?int $offset = null): array
+    {
+        return $this->repository->findBy($criteria, $orderBy, $limit, $offset);
+    }
+
+    /**
+     * @return array|Calendar[]
+     */
+    public function findByAccompanyingPeriod(AccompanyingPeriod $period, ?array $orderBy = null, ?int $limit = null, ?int $offset = null): array
+    {
+        return $this->findBy(
+            [
+                'accompanyingPeriod' => $period,
+            ],
+            $orderBy,
+            $limit,
+            $orderBy
+        );
+    }
+
+    public function findOneBy(array $criteria): ?Calendar
+    {
+        return $this->repository->findOneBy($criteria);
+    }
+
+    public function getClassName()
+    {
+        return Calendar::class;
+    }
 }
diff --git a/src/Bundle/ChillCalendarBundle/Repository/InviteRepository.php b/src/Bundle/ChillCalendarBundle/Repository/InviteRepository.php
index 53aa8b2a1..450626cef 100644
--- a/src/Bundle/ChillCalendarBundle/Repository/InviteRepository.php
+++ b/src/Bundle/ChillCalendarBundle/Repository/InviteRepository.php
@@ -12,48 +12,47 @@ declare(strict_types=1);
 namespace Chill\CalendarBundle\Repository;
 
 use Chill\CalendarBundle\Entity\Invite;
-use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
-use Doctrine\Persistence\ManagerRegistry;
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityRepository;
+use Doctrine\Persistence\ObjectRepository;
 
-/**
- * @method Invite|null find($id, $lockMode = null, $lockVersion = null)
- * @method Invite|null findOneBy(array $criteria, array $orderBy = null)
- * @method Invite[]    findAll()
- * @method Invite[]    findBy(array $criteria, array $orderBy = null, $limit = null, $offset = null)
- */
-class InviteRepository extends ServiceEntityRepository
+class InviteRepository implements ObjectRepository
 {
-    public function __construct(ManagerRegistry $registry)
+    private EntityRepository $entityRepository;
+
+    public function __construct(EntityManagerInterface $em)
     {
-        parent::__construct($registry, Invite::class);
+        $this->entityRepository = $em->getRepository(Invite::class);
     }
 
-    // /**
-    //  * @return Invite[] Returns an array of Invite objects
-    //  */
-    /*
-    public function findByExampleField($value)
+    public function find($id): ?Invite
     {
-        return $this->createQueryBuilder('i')
-            ->andWhere('i.exampleField = :val')
-            ->setParameter('val', $value)
-            ->orderBy('i.id', 'ASC')
-            ->setMaxResults(10)
-            ->getQuery()
-            ->getResult()
-        ;
+        return $this->entityRepository->find($id);
     }
-     */
 
-    /*
-    public function findOneBySomeField($value): ?Invite
-    {
-        return $this->createQueryBuilder('i')
-            ->andWhere('i.exampleField = :val')
-            ->setParameter('val', $value)
-            ->getQuery()
-            ->getOneOrNullResult()
-        ;
-    }
+    /**
+     * @return array|Invite[]
      */
+    public function findAll(): array
+    {
+        return $this->entityRepository->findAll();
+    }
+
+    /**
+     * @return array|Invite[]
+     */
+    public function findBy(array $criteria, ?array $orderBy = null, ?int $limit = null, ?int $offset = null)
+    {
+        return $this->entityRepository->findBy($criteria, $orderBy, $limit, $offset);
+    }
+
+    public function findOneBy(array $criteria): ?Invite
+    {
+        return $this->entityRepository->findOneBy($criteria);
+    }
+
+    public function getClassName(): string
+    {
+        return Invite::class;
+    }
 }
diff --git a/src/Bundle/ChillCalendarBundle/Resources/public/vuejs/Calendar/store/actions.js b/src/Bundle/ChillCalendarBundle/Resources/public/vuejs/Calendar/store/actions.js
index d57592748..ab24d17ac 100644
--- a/src/Bundle/ChillCalendarBundle/Resources/public/vuejs/Calendar/store/actions.js
+++ b/src/Bundle/ChillCalendarBundle/Resources/public/vuejs/Calendar/store/actions.js
@@ -172,18 +172,13 @@ export default {
   },
   setMainUser({commit, dispatch, state}, mainUser) {
     console.log('setMainUser', mainUser);
-    if (state.activity.mainUser.id !== mainUser.id) {
-      let mainUserInput = document.getElementById("chill_activitybundle_activity_mainUser");
-      mainUserInput.value = Number(mainUser.id);
 
-      if (state.activity.calendarRange !== null || state.activity.startDate !== null || state.acdtivity.endDate !== null) {
-        dispatch('associateCalendarToRange', { range: null });
-      }
+    let mainUserInput = document.getElementById("chill_activitybundle_activity_mainUser");
+    mainUserInput.value = Number(mainUser.id);
 
+    return dispatch('associateCalendarToRange', { range: null }).then(() => {
       commit('setMainUser', mainUser);
-    }
-
-    return Promise.resolve();
+    });
   },
 
   // Location