Can we change the retainage % on the purchase order after receiving & vouchering partial lines

Hello, We have a lumpsum Purchase order with only the extended amount.

We are trying to see whether we could change the retainage % in P4310 application, after receiving items (the amounts) partially. We reduce the retainage % after receiving say half of the order.

Is there anyway we could change it?

Know it can be change in the voucher match, but we want it in P4310, so the purchasing users will see the new %.

Thanks !