Can you amend a Vat invoice that has been paid in advance of the service being delivered or do you have to raise a Credit and Re-Invoice? This is the delivery of training to a Commercial UK company, the invoice was issued and paid in August with the training taking place in in the future however the customer has now advised a substitution of delegate. Can this be actioned via amending and re-issuing an invoice or does a credit and re-invoice have to be actioned. There is no change to company name, date of invoice, date of training, training course being delivered, course amount or vat being charged. It is simply a change in delegate name.