Client made an AP payment for period 2019-11

Then reversed it by accident in 2020-01 which was wrong it should have been 2019-12  (confusion about end of year December)

Does anyone know how to un-reverse a AP Payment reversal in A/P so they can reverse it in the correct period.

Because AP Control, Bank total wrong for 2019-12 etc.

I am thinking only hope might be Bank entries using AP Control Account and Bank Account

any help/ideas would be much appreciated