First things first, learn how to cancel bookings or delete individual participants here.
If you want to make refund to your customer, you can do so during the cancellation process. You simply have click on "Yes" next to "Issue refund":
You can then choose between two reimburcement options:
Refund using the payment method that the customer initially used to pay ( see screenshot "Immediate transfer" -> "Refund with immediate transfer")
Refund wuth a voucher - the latter is generated automatically and can be viewed and downloaded under Orders -> Vouchers.
It is, of course, up to you how much you would like to refund and whether you'd like to make a full or partial refund.
If you want to make a refund using online payment methods, such as Immediate transfer or refund to a credit card, and you do not have enough funds in your escrow account, the following message will appear:
In this case, it is not possible to make a monetary refund. Yan you still make a refund with a gift voucher. Find out here how this works and why this may be an even better option.
There is also the possibility to queue the refund, so that it will be automatically processed once you have enough funds available on your escrow account: