diff --git a/phpstan.neon b/phpstan.neon
index 5e8d0fbe..9c3358ee 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -23,6 +23,10 @@ parameters:
 		     # 3rd party library
 		     message: '#Access to an undefined property Skautis\\Skautis::\$OrganizationUnit\.#'
 		     path: src\Skautis\SkautisService.php
+		 -
+		     # database manipulation
+		     message: '#kissj\\Participant\\Patrol\\PatrolParticipant::\$patrolLeader \(kissj\\Participant\\Patrol\\PatrolLeader\) does not accept null\.#'
+		     path: src\Participant\ParticipantService.php
 	exceptions:
 		uncheckedExceptionRegexes:
 			- '#Exception#'
diff --git a/src/Participant/ParticipantService.php b/src/Participant/ParticipantService.php
index ab5dab99..ce0b1205 100755
--- a/src/Participant/ParticipantService.php
+++ b/src/Participant/ParticipantService.php
@@ -12,6 +12,7 @@
 use kissj\Mailer\PhpMailerWrapper;
 use kissj\Participant\Guest\Guest;
 use kissj\Participant\Patrol\PatrolLeader;
+use kissj\Participant\Patrol\PatrolParticipant;
 use kissj\Participant\Troop\TroopLeader;
 use kissj\Participant\Troop\TroopParticipant;
 use kissj\Participant\Troop\TroopParticipantRepository;
@@ -499,6 +500,14 @@ public function tryChangeRoleWithMessages(string $roleFromBody, Participant $par
 
             return false;
         }
+        
+        if ($participant instanceof PatrolParticipant) {
+            $participant->patrolLeader = null;
+        }
+        
+        if ($participant instanceof TroopParticipant) {
+            $participant->troopLeader = null;
+        }
 
         $participant->role = $role;
         $this->participantRepository->persist($participant);