To correct a previous allocation, you first need to unallocate the transactions and then redo the allocation.
Unallocating a transaction can be done in the Allocation Correction module screen as follows:
Ribbon style menu:
On the Creditors tab, in the Allocation section, click Allocation, Correction
Use the Allocations Corrections search screen to enter the relevant information to find the transaction(s)
Click Display
Locate and select the transaction(s)
Double-click the transactions to be unallocated - they should balance to zero
Click OK
Then on the Update Allocations screen, enter the Date for the allocation and select the year/period. The year/period selected should be the same period as for the original allocation.
Classic / Module Menus style menu:
On the navigation bar, select Purchase Ledger followed by Allocations, Correction
Use the Allocations Correction search screen to enter the relevant information to find the transaction(s)
Click Display
Locate and select the transaction(s)
Double-click the transactions to be unallocated - they should balance to zero
Click OK
Then on the Update Allocations screen, enter the Date for the allocation and select the year/period. The year/period selected should be the same period as for the original allocation.