Cannot clear negative encumbrance from PO

Hello,

I am dealing with an issue with a dispatched PO that contains two lines with negative amounts that were split into two vouchers that are already finalized, budget-checked and posted.

The issue is that the user appears to have undercounted in one line by one cent in one voucher, and then tried to compensate for that by increasing the other negative line by an additional cent, which does not actually "balance out" the encumbrance in the PO because additional encumbrance cannot be added to the PO. There the PO have an encumbrance of $ -0.01 currently.

What can be done to clear this?