How to add notes to an approved Requisition from the buyer work centre, requisition pool

Is there any way to capture notes against the requisition line in the buyer work centre?  Buyers would like to be able to add notes/history without having to return the requisition to the requestor.

For our client it is frequent for the buyer to interact with the requestor over email, we would like to know if this additional information can be stored, by the buyer anywhere on the requisition?

We are on EBS 12.2.