How to modify an incorrect Organization in a PO

 What is the correct method to modify an org in a PO if the PO was created with the incorrect org?  We've had a couple of instances where a requestor entered the wrong org and the PO was prepared based on the requisition's incorrect information. When the problem was identified we added a shipment with the correct org and then deleted the shipment with the incorrect org; this however has resulted in the PO being stuck in an In-process status and cannot be opened.  This method used to work for us but perhaps in newer releases it doesn't, we use