Cannot voucher a final receipt due to KK_CLOSE_FLAG on the PO

Hello everyone,I have a receipt that we are trying to copy into a voucher, but it's not available for selection.  The reason is because Line 4 of my PO has a KK_CLOSE_FLAG = Y.

How can I change this?

I have tried:
Unfinalizing the PO
Unfinalizing the PO Line
Unfinalizing the PO schedule

Nothing has worked.

Also--how do I know if  voucher or a PO is finalized? 

Thanks,
Gina