Amending Subcontractor PO

If a subcontractor purchase order was originally input with the wrong Vendor # , the invoice comes in later & you discover you cannot post an invoice against this PO b/c it's wrong. . .How do you correct?
The subcontract PO has already been "approved" & VP wants the PO to be "pending" in order to make changes. . .so, can you change the PO from Approved to Pending?? Or how do you handle?

In order to adjust the Vendor you must un-interface the subcontract agreement. These steps are listed in the documentation, with in the Branch Administration Manual, in the section for Subcontract Agreements, on page 19, under "MODIFYING AN INTERFACED OR NON-INTERFACED SUBCONTRACT AGREEEMENT". Once the agreement has been un-interfaced modifications can be made.