How does credit card pre-authorization work?

The pre-authorisation is not a payment, but a temporary reservation/deduction of a certain amount on the customer's credit card. For example at hotels, it is often equal to one or two nights of the booking. You can always convert the pre-authorisation into a payment later if, for example, the customer does not show up or there are additional charges. You can also cancel a pre-authorisation if payment is made in any other way.