Diagnosis
You can only reject an order item in third-party order processing oncethe purchase order item has been deleted. When you delete it, youshould also ensure that the vendor delivers the goods directly to thecustomer if the order has not been rejected.
If you cannot delete the purchase order, then you should not reject thesales order because the goods have probably reached the customer andshould then be billed. At this point, the customer can no longer rejectthe order item.