As each customer/supplier has a tax code specified by the tax group associated with it, to change the tax rate a different tax group needs to be associated – see details in how to set a customers VAT rate or how to set a suppliers VA
As each customer/supplier has a tax code specified by the tax group associated with it, to change the tax rate a different tax group needs to be associated – see details in how to set a customers VAT rate or how to set a suppliers VA