You can only change your VAT method if you do not yet have any postings in the calendar year for which you want to change the VAT method.
If you have already entered postings for this calendar year, then the VAT method cannot be changed. However, if you still want to change the VAT method in any case, we recommend the following procedure:
Invoices, credit notes, and vendor invoices
Reset all documents belonging to these three types to draft status. This reverses the posting, and you can reissue the invoices again once the status has been changed to draft. You may have to update the VAT rates on the documents after changing the status, because the old rates will no longer be valid under the new method.
Expenses and manual postings
For expenses and manual postings, we recommend deleting the VAT rates in the postings and then resaving them. After changing your VAT method, you can set the new VAT rates for your postings.
Please note: This is only possible if you have not yet closed a VAT period or fiscal year in the calendar year.