diff --git a/lib/Db/AclMapper.php b/lib/Db/AclMapper.php
index d34738d82..327d8aa34 100644
--- a/lib/Db/AclMapper.php
+++ b/lib/Db/AclMapper.php
@@ -69,28 +69,14 @@ class AclMapper extends DeckMapper implements IPermissionMapper {
 			'newOwner' => $newOwnerId,
 			'type' => Acl::PERMISSION_TYPE_USER
 		];
-		//We want preserve permissions from both users
-		$sql = "UPDATE `{$this->tableName}` AS `source` 
-                    LEFT JOIN `{$this->tableName}` AS `target` 
-                    ON `target`.`participant` = :newOwner AND `target`.`type` = :type 
-                    SET `source`.`permission_edit` =(`source`.`permission_edit` || `target`.`permission_edit`), 
-                        `source`.`permission_share` =(`source`.`permission_share` || `target`.`permission_share`), 
-                        `source`.`permission_manage` =(`source`.`permission_manage` || `target`.`permission_manage`) 
-                    WHERE `source`.`participant` = :owner AND `source`.`type` = :type";
-		$stmt = $this->execute($sql, $params);
-		$stmt->closeCursor();
-		//We can't transfer acl if target already in acl
+
+		// Drop existing ACL rules for the new owner
 		$sql = "DELETE FROM `{$this->tableName}` 
                     WHERE `participant` = :newOwner 
                         AND `type` = :type 
                         AND EXISTS (SELECT `id` FROM (SELECT `id` FROM `{$this->tableName}` 
-                                    WHERE `participant` = :owner AND `type` = :type) as tmp)";
+                                    WHERE `participant` = :newOwner AND `type` = :type) as tmp)";
 		$stmt = $this->execute($sql, $params);
 		$stmt->closeCursor();
-		//Now we can transfer without errors
-		$sqlUpdate = "UPDATE `{$this->tableName}`  
-                        SET `participant` = :newOwner WHERE `participant` = :owner AND `type` = :type";
-		$stmt = $this->execute($sqlUpdate, $params);
-		$stmt->closeCursor();
 	}
 }