You can perform a refund from Caterbook for an existing Accepted Caterpay payment (transactions change state from Captured to Accepted by the acquirer overnight, therefore in most cases, a refund can only be actioned the following day, directly from within Caterbook).
To perform a refund, go to the Finance tab from within the booking.
In the screenshot below you'll see two red arrows forming a circle at the end of transaction where tokenised card from an OTA was charged. Clicking this icon will enable you to process a refund for any amount up to the original value, within 180 days of the charging date.
If you wanted to refund the initial payment on the same day as it was made, and it has not yet been Accepted by the acquirer it's possible to Cancel the transaction completely, and prevent it from being processed for settlement. This is also useful where the initial payment has been charged for the incorrect amount.