How to change the Supplier ( by Buyer) on Requisition during the Approval process

Content

Our current legacy process is requester to put in a requisition for a product without assigning or assigning the supplier and send for approval.

In the approval process, it has to go to the buyer team to look at the price, supplier and some other tasks.

Buyer to over-write the price, vendor and continue.

How does buyer change/assign a  supplier during the approval process, I can do attachments during the approval process, tested and works.

We are on Cloud R12 and other issue is Manage Requisitions search is also not working, I tried searching based on the requestor and requisition but nothing works.