Cancel credit note

This seems so basic that I am sure I have missed something. There were two outstanding purchase invoices on the system for my client. I understood that they were not going to be paid. Since they had already been included on a VAT return I could not void but credit noted them instead. It turns out that they will be paid in the end and therefore need to reverse/void the credit note. The credit note has not yet been included in a vat return. It should be fairly straight forward void the CN to do that but that button seems to be missing on the CN. Something obvious perhaps forgotten by the development team. A workaround to recreate the invoices seems really unnecessary and untidy in the books.