Terminate buyer's PO issue

There's the scenario:

     1. 5 PO created by a terminate buyer, and the PO have been approved.

     2. Other buyer shared same position with the terminate buyer cannot find this 5 PO in PO Summary window

     3. Only approver can find this 5 PO

Now this 5 PO need to be modified, but only this approver can change the PO, but if we do this, no higher approver can approve this PO.

There's the questions:

Why this 5 PO cannot be found by other buyer?

Is there a solution to make buyers find this 5 PO?

What can we do to modify this 5 PO and get approve?