If a payment is reversed against a Payment Request, a Reversal VAT Receipt is generated and is required to be sent to the tenant the same way as a regular VAT Receipt (unless the original VAT Receipt was never sent).

The green button at the top of the Reversal VAT Receipt screen will let you view the original VAT Receipt it is related to. The reference field on the Reversal VAT Receipt also displays the original VAT Receipt number it's related to.

A Reversal VAT Receipt looks the same as a regular VAT Receipt, but with negative values.