1. Access VAT Rate Modification In Sage 100, you can modify VAT rates directly from the document header (invoice, quote, etc.). Simply click Create/Modify, then VAT Rates. This option allows you to adjust the rates applied to lines already entered. 2. Three Modification Modes Available Once in the Rates menu, Sage offers you three options: VAT and Accounts: Modifies the rate and updates the accounting accounts. VAT Only: Changes only the rate without affecting the accounts. Ignore: Keeps existing rates and only applies the new rates to the added lines. 3. Adding a Missing Rate Without Re-entering If you forgot to apply the 7% rate, select "VAT Only" to have Sage update the relevant lines without modifying the accounts. This avoids having to delete and re-enter all the lines.