diff --git a/src/Bundle/ChillTicketBundle/src/Action/Ticket/Handler/SetCallerCommandHandler.php b/src/Bundle/ChillTicketBundle/src/Action/Ticket/Handler/SetCallerCommandHandler.php
new file mode 100644
index 000000000..ae37f3945
--- /dev/null
+++ b/src/Bundle/ChillTicketBundle/src/Action/Ticket/Handler/SetCallerCommandHandler.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\TicketBundle\Action\Ticket\Handler;
+
+use Chill\TicketBundle\Action\Ticket\SetCallerCommand;
+use Chill\TicketBundle\Entity\CallerHistory;
+use Chill\TicketBundle\Entity\Ticket;
+use Symfony\Component\Clock\ClockInterface;
+
+/**
+ * Handler for setting the caller of a ticket.
+ */
+class SetCallerCommandHandler
+{
+    public function __construct(private readonly ClockInterface $clock) {}
+
+    public function __invoke(Ticket $ticket, SetCallerCommand $command): Ticket
+    {
+        // If the ticket already has the requested caller, return it without changes
+        $currentCaller = $ticket->getCaller();
+        if ($currentCaller === $command->caller) {
+            return $ticket;
+        }
+
+        // End the current caller history (if any)
+        foreach ($ticket->getCallerHistories() as $callerHistory) {
+            if (null === $callerHistory->getEndDate()) {
+                $callerHistory->setEndDate($this->clock->now());
+            }
+        }
+
+        // Create a new caller history with the new caller
+        new CallerHistory(
+            $command->caller,
+            $ticket,
+            $this->clock->now(),
+        );
+
+        return $ticket;
+    }
+}
diff --git a/src/Bundle/ChillTicketBundle/src/Action/Ticket/SetCallerCommand.php b/src/Bundle/ChillTicketBundle/src/Action/Ticket/SetCallerCommand.php
new file mode 100644
index 000000000..2589abac4
--- /dev/null
+++ b/src/Bundle/ChillTicketBundle/src/Action/Ticket/SetCallerCommand.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\TicketBundle\Action\Ticket;
+
+use Chill\PersonBundle\Entity\Person;
+use Chill\ThirdPartyBundle\Entity\ThirdParty;
+
+/**
+ * Command to set the caller of a ticket.
+ * The caller can be either a Person or a ThirdParty.
+ */
+final readonly class SetCallerCommand
+{
+    /**
+     * @param Person|ThirdParty|null $caller The caller to associate with the ticket
+     */
+    public function __construct(
+        public Person|ThirdParty|null $caller,
+    ) {}
+}
diff --git a/src/Bundle/ChillTicketBundle/tests/Action/Ticket/Handler/SetCallerCommandHandlerTest.php b/src/Bundle/ChillTicketBundle/tests/Action/Ticket/Handler/SetCallerCommandHandlerTest.php
new file mode 100644
index 000000000..e2e8a642b
--- /dev/null
+++ b/src/Bundle/ChillTicketBundle/tests/Action/Ticket/Handler/SetCallerCommandHandlerTest.php
@@ -0,0 +1,178 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\TicketBundle\Tests\Action\Ticket\Handler;
+
+use Chill\PersonBundle\Entity\Person;
+use Chill\ThirdPartyBundle\Entity\ThirdParty;
+use Chill\TicketBundle\Action\Ticket\Handler\SetCallerCommandHandler;
+use Chill\TicketBundle\Action\Ticket\SetCallerCommand;
+use Chill\TicketBundle\Entity\CallerHistory;
+use Chill\TicketBundle\Entity\Ticket;
+use PHPUnit\Framework\TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Symfony\Component\Clock\ClockInterface;
+use Symfony\Component\Clock\MockClock;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+class SetCallerCommandHandlerTest extends TestCase
+{
+    use ProphecyTrait;
+
+    private \DateTimeImmutable $now;
+    private ClockInterface $clock;
+    private SetCallerCommandHandler $handler;
+
+    protected function setUp(): void
+    {
+        $this->now = new \DateTimeImmutable('2023-01-01 12:00:00');
+        $this->clock = new MockClock($this->now);
+        $this->handler = new SetCallerCommandHandler($this->clock);
+    }
+
+    public function testSetPersonAsCaller(): void
+    {
+        // Arrange
+        $ticket = new Ticket();
+        $person = new Person();
+        $command = new SetCallerCommand($person);
+
+        // Act
+        $result = ($this->handler)($ticket, $command);
+
+        // Assert
+        self::assertSame($ticket, $result);
+        self::assertSame($person, $ticket->getCaller());
+        self::assertCount(1, $ticket->getCallerHistories());
+
+        $callerHistory = $ticket->getCallerHistories()->first();
+        self::assertInstanceOf(CallerHistory::class, $callerHistory);
+        self::assertSame($person, $callerHistory->getPerson());
+        self::assertNull($callerHistory->getThirdParty());
+        self::assertEquals($this->now->getTimestamp(), $callerHistory->getStartDate()->getTimestamp());
+        self::assertNull($callerHistory->getEndDate());
+    }
+
+    public function testSetThirdPartyAsCaller(): void
+    {
+        // Arrange
+        $ticket = new Ticket();
+        $thirdParty = new ThirdParty();
+        $command = new SetCallerCommand($thirdParty);
+
+        // Act
+        $result = ($this->handler)($ticket, $command);
+
+        // Assert
+        self::assertSame($ticket, $result);
+        self::assertSame($thirdParty, $ticket->getCaller());
+        self::assertCount(1, $ticket->getCallerHistories());
+
+        $callerHistory = $ticket->getCallerHistories()->first();
+        self::assertInstanceOf(CallerHistory::class, $callerHistory);
+        self::assertNull($callerHistory->getPerson());
+        self::assertSame($thirdParty, $callerHistory->getThirdParty());
+        self::assertEquals($this->now->getTimestamp(), $callerHistory->getStartDate()->getTimestamp());
+        self::assertNull($callerHistory->getEndDate());
+    }
+
+    public function testChangeCallerFromPersonToThirdParty(): void
+    {
+        // Arrange
+        $ticket = new Ticket();
+        $person = new Person();
+        $thirdParty = new ThirdParty();
+
+        // Set initial person caller
+        $initialCallerHistory = new CallerHistory($person, $ticket, $this->now);
+        $initialCallerHistory->setPerson($person);
+
+        // Create command to change to third party
+        $command = new SetCallerCommand($thirdParty);
+
+        // Act
+        $this->clock->modify('+ 10 minutes');
+        $result = ($this->handler)($ticket, $command);
+
+        // Assert
+        self::assertSame($ticket, $result);
+        self::assertSame($thirdParty, $ticket->getCaller());
+        self::assertCount(2, $ticket->getCallerHistories());
+
+        // Check that the first history is ended
+        $firstCallerHistory = $ticket->getCallerHistories()->first();
+        self::assertSame($person, $firstCallerHistory->getPerson());
+        self::assertEquals($this->clock->now()->getTimestamp(), $firstCallerHistory->getEndDate()->getTimestamp());
+
+        // Check that the new history is created correctly
+        $lastCallerHistory = $ticket->getCallerHistories()->last();
+        self::assertNull($lastCallerHistory->getPerson());
+        self::assertSame($thirdParty, $lastCallerHistory->getThirdParty());
+        self::assertSame($this->clock->now()->getTimestamp(), $lastCallerHistory->getStartDate()->getTimestamp());
+        self::assertNull($lastCallerHistory->getEndDate());
+    }
+
+    public function testRemoveCaller(): void
+    {
+        // Arrange
+        $ticket = new Ticket();
+        $person = new Person();
+
+        // Set initial person caller
+        $initialCallerHistory = new CallerHistory($person, $ticket, $this->now);
+
+        // Create command to remove caller
+        $command = new SetCallerCommand(null);
+
+        // Act
+        $result = ($this->handler)($ticket, $command);
+
+        // Assert
+        self::assertSame($ticket, $result);
+        self::assertNull($ticket->getCaller());
+        self::assertCount(2, $ticket->getCallerHistories());
+
+        // Check that the history is ended
+        $callerHistory = $ticket->getCallerHistories()->first();
+        self::assertSame($person, $callerHistory->getPerson());
+        self::assertEquals($this->now->getTimestamp(), $callerHistory->getEndDate()->getTimestamp());
+    }
+
+    public function testNoChangeWhenCallerIsAlreadySet(): void
+    {
+        // Arrange
+        $ticket = new Ticket();
+        $person = new Person();
+
+        // Set initial person caller
+        $initialCallerHistory = new CallerHistory($person, $ticket, $this->now);
+
+        // Create command with the same person
+        $command = new SetCallerCommand($person);
+
+        // Act
+        $result = ($this->handler)($ticket, $command);
+
+        // Assert
+        self::assertSame($ticket, $result);
+        self::assertSame($person, $ticket->getCaller());
+        self::assertCount(1, $ticket->getCallerHistories());
+
+        // Check that the history is unchanged
+        $callerHistory = $ticket->getCallerHistories()->first();
+        self::assertSame($person, $callerHistory->getPerson());
+        self::assertNull($callerHistory->getEndDate());
+    }
+}