API to discard invoice lines

Hello,

We have a case where-in few Invoice lines are matched to PO and accounted. However the invoice is still has got hold. We need to discard these few invoice lines that are matched to PO and accounted.  When we are trying to discard it through form, we are  getting the erro message "Discarding this invoice line is not allowed as quantity/amount billed on the purchase order distribution will be reduced below zero."

We  tried applying the patch patch 24961235 as per Oracle knowledge base. However, the error still persists and we are unable to perform the desired action plan.