Invoice Hold: Unable to correct line variance

Hello Gurus,

We have an invoice which was held by system after validating the invoice with prepayment application.

"Line Variance: Total of Invoice Lines does not equal Invoice Amount"

The invoice header amount and invoice line amount have the same values. But the invoice distributions total are not equal.

How do I correct this? I can no longer edit/update distribution amount because field is already greyed-out.

Invoice is also partially accounted, and in Needs Revalidation status.

Thank you for your help.