Hello Community Users!! We just wanted to come onto this thread and add some clarification and updates now MTD is in play.
Because of the way Making Tax Digital works on the Flat Rate Scheme, you can't edit or delete transactions in a return that has already been filed.
If you need to make changes, you'll need to create a journal entry to reverse the original transaction by reversing the amounts of the debits and credits. Then, if needed, create a new transaction with the correct information. See how to create or reverse a journal entry.
The best way to make sure it's reversed correctly is to use the transaction journal for the transaction you want to change and reverse the amounts that are in the debits and credits column. Enter the applicable VAT code(s) in the VAT column of the journal entry next to the line(s) that had VAT in the original transaction.
We hope this helps you any questions just reply to this thread, we'd be happy to help.