allow an employee other than the "Requester" or "Preparer" on a Req to do the self service receipt

I have a unique case in which the Req/PO line for "Amount" need to be received by someone other than

a. Preparer of the requisition

b. Requester on the PO /Req line

Business has a specific role in the organization called "Service technical Rep" (STR) who reviews and approves on site work based on policies and procedures so that Suppliers get paid

Is there any type of privilege or role that can be given to this person to be able to do the receipt

(We looked at Complex work Purchase Orders - but it will be an overkill since we have to do separate PO for quantity based lines and amount based lines )