Personalization: Approve Requisition after Custom flag checked

Hi guys,

We have custom requirement for po requisition approval. Can we put condition that the approve button should worked if 'a flag' was clicked.

A flag means like i create an item and define it as attribute field on po_requisition _headers_all table.

That requirement submitted by our user because they need a checkpoint for calculate their service rate between the date of their approval and the date when po requisition document have received.

I need the document received is save in the system. So i need that as flag. And if that can save in system, so i can create a report for the service rate comparison.