When you post a supplier invoice with a postponed accounting tax code, a purchase credit for the postponed VAT amount is automatically posted and allocated to the invoice.

Once these transactions are VAT reconciled, if you try to edit or delete them, you see the above message. This simply means that as these transactions are linked, you must manually reverse them instead. 

Don't worry, this is easy to do by posting opposite entries for both the invoice and credit transaction.

1. Click Transactions, then locate the linked invoice and credit you want to edit or delete.
2. Make a note of the invoice date, nominal code, net, tax amount and tax code.
3. Make a note of the same details for the linked credit transaction.
4. Click Suppliers, click Batch Credit then enter the following details:

   Supplier	Date	N/C	Net	T/C	VAT
   Supplier reference	Original invoice date	Original invoice nominal code	Original invoice net amount	Original invoice tax code	Original invoice VAT amount

5. Click Save then click Close.
6. Click Suppliers, click Batch Invoice then enter the following details:

   Supplier	Date	N/C	Net	T/C	VAT
   Supplier reference	Original credit date	Original credit nominal code	Original credit net amount	Original credit tax code	Original credit VAT amount

7. Click Save then click Close.

That's it. You've manually reversed the transactions. If required, you can now re-post them with the correct details.