To reverse a transaction posted to the wrong period or for the wrong amount, create and post an opposing journal in the same period as the original. Ribbon menu:
Click Financials in the main menu.
Click Journal or VAT Journal, depending on the type of the original.
Optionally, click the Options icon and select Batch Transaction.
Select the same period as the original posting.
Tab to the detail page. Enter lines for the same nominal accounts and amounts as the original, but with opposite credit/debit types — for example, a credit line where the original had a debit.
Click Save to post the journal or save it to the batch.
Classic/module menu:
Click Nominal Ledger in the navigation bar.
Click Transactions > Journals or VAT Journals, depending on the type of the original.
Then follow from step 3 in the ribbon menu steps above.
Once posted, the original transaction is offset. The original journal remains visible in the ledger.