Can I undo modification on PO header?

Dear all

The customer user did following action and he wander if he can roll back.

1. There're hundreds of standard POs in "approved" status.
2. A new user change the supplier for all of them, he didn't use "Mass Update of Buyer Name on Purchasing Documents" concurrent
3. So these POs are change to "require reapprove" status.
4. No data created in PO archive table but revision number was change to 1 in PO headers.

The customer hope to know how to roll it back without approve again and make the revision number in PO headers change to 0.

Best regards
Peter Li