I have a bill I need to enter to a particular invoice, we'll call it bill No. 3. I have already added bill no. 2 for vendor A, when the message comes up to select an open purchase order to receive, I have already selected this PO 3. When I have a second bill (bill 2) come in from the same Vendor A, lets say for an additional shipping cost for this PO 3, I need to select the same PO 3 to receive. However, the PO is already closed. What is the correct way to deal with this issue?