we recently had an amount open on PO RNI that was not supposed to be there.  Our PO was still open at that point and we were able to go to AP-C and enter the po invoice again then do a credit voucher to relieve the customer ledger of this amount.

If you go to PO-K (Close Purchase Orders) and close the specific PO that should not be on the RNI report.  The PO will no longer appear on your RNI report.

It was just brought to my attention something weird.  If I run a complete RNI report for all PO's (everything), those problem PO's do not show as being open.  They do not show on the report at all.  But if I run a "Receiving Report" for those problem PO's,  the report shows the amounts still in RNI.  And if I try to run a "Received not Invoiced" Report on those problem PO's, EVO says there are no receivings.
 
So the PO's do not show on the complete "RNI Report", but they show on individual "Receiving Reports" as still being in RNI.  I just want to get rid of them so they do not show on a "Receiving Report" as being open.