Navigate to Data⇒Finance⇒Tax Code
Locate the tax group you wish to amend, using the Search function if required. Click on the tax group that you want to amend, then click on the New button if you wish to change a VAT rate.
NOTE - if the VAT rate changes, DO NOT just change the % on an existing tax code - this may affect current and historical transactions and may corrupt reports you have created. Create a new tax code and select it as the current VAT code for that group
Complete the new tax code details and click Update followed by Clear
Use the drop down list to assign the new tax code to the group and then click Save
All new transactions for customers/suppliers with this tax group selected will have the new tax rate applied