Tracking of PO changes before approval

We are in 12.1.3.  When any change in  an Approved PO is done, revision gets incremented and  changes to requires Reapproval. Is there a way to check what has been changed in the PO  by the Approver - before approving the PO. We have  the functionality like PO change history which will show all the changes pertaining to the specific Revision or all revision. But this will show the changes post approval of PO. It will not show anything in pending - i.e. Any PO (changes) requires Reapproval status is not shown.

There is  form called  'Pending  Purchase Order changes' But this also does not  show up the PO's with Requires reapporval Status. Is there anyway  we can check the changes in PO prior to approval.