diff --git a/db/changes/232601/00-packingSiteAdvanced.sql b/db/changes/232601/00-packingSiteAdvanced.sql
index 63c348fcc..0e33744cd 100644
--- a/db/changes/232601/00-packingSiteAdvanced.sql
+++ b/db/changes/232601/00-packingSiteAdvanced.sql
@@ -12,7 +12,7 @@ INSERT INTO `salix`.`ACL` (`model`, `property`, `accessType`, `permission`, `pri
     VALUES
         ('PackingSiteAdvanced', '*', '*', 'ALLOW', 'ROLE', 'production');
 
-DROP PROCEDURE IF EXISTS `vn`.`packingSite_startCollection`;
+ DROP PROCEDURE IF EXISTS `vn`.`packingSite_startCollection`;
 
 DELIMITER $$
 $$
@@ -22,40 +22,48 @@ proc: BEGIN
  * @param vSelf packingSite id
  * @param vTicketFk A ticket id from the collection to start
  */
-	DECLARE vNewCollectionFk INT;
-	DECLARE vIsAdvanced BOOL;
-	DECLARE vOldCollectionFk INT;
-	DECLARE vIsPackingByOther BOOL;
+	DECLARE vExists BOOL;
+    DECLARE vIsAdvanced BOOL;
+    DECLARE vNewCollectionFk INT;
+    DECLARE vOldCollectionFk INT;
+    DECLARE vIsPackingByOther BOOL;
 
-	SELECT COUNT(*) > 0
-		INTO vIsAdvanced
-		FROM packingSiteAdvanced
-		WHERE ticketFk = vTicketFk;
+    SELECT id, collectionFk
+        INTO vExists, vOldCollectionFk
+        FROM packingSite
+        WHERE id = vSelf;
 
-	IF vIsAdvanced THEN
-		LEAVE proc;
-	END IF;
+    IF NOT vExists THEN
+        CALL util.throw('packingSiteNotExists');
+    END IF;
 
-	SELECT collectionFk INTO vNewCollectionFk
-		FROM ticketCollection WHERE ticketFk = vTicketFk;
+    SELECT COUNT(*) > 0
+        INTO vIsAdvanced
+        FROM packingSiteAdvanced
+        WHERE ticketFk = vTicketFk;
 
-	SELECT collectionFk INTO vOldCollectionFk
-		FROM packingSite WHERE id = vSelf;
+    IF vIsAdvanced THEN
+        LEAVE proc;
+    END IF;
 
-	IF NOT (vOldCollectionFk <=> vNewCollectionFk) THEN
-		SELECT COUNT(*) > 0
-			INTO vIsPackingByOther
-			FROM packingSite
-			WHERE id <> vSelf
-				AND collectionFk = vOldCollectionFk;
+    SELECT collectionFk INTO vNewCollectionFk
+        FROM ticketCollection WHERE ticketFk = vTicketFk;
 
-		IF NOT vIsPackingByOther AND NOT collection_isPacked(vOldCollectionFk) AND vSelf IS NOT NULL THEN
-			CALL util.throw('cannotChangeCollection');
-		END IF;
-	END IF;
+    IF vOldCollectionFk IS NOT NULL
+    AND vOldCollectionFk <> vNewCollectionFk THEN
+        SELECT COUNT(*) > 0
+            INTO vIsPackingByOther
+            FROM packingSite
+            WHERE id <> vSelf
+                AND collectionFk = vOldCollectionFk;
 
-	UPDATE packingSite SET collectionFk = vNewCollectionFk
-		WHERE id = vSelf;
+        IF NOT vIsPackingByOther AND NOT collection_isPacked(vOldCollectionFk) THEN
+            CALL util.throw('cannotChangeCollection');
+        END IF;
+    END IF;
+
+    UPDATE packingSite SET collectionFk = vNewCollectionFk
+        WHERE id = vSelf;
 END$$
 DELIMITER ;