It is always possible to cancel a confirmed booking. Find out how to do that in this article. 

The Owner can choose which cancellation rules apply to their Vehicle. The cancellation rules that the Owner can choose from are "Standard", "Flexible" or "Strict" according to the following table:

You'll find the cancellation policy of your booked vehicle in either the booking page under "Cancellation" or on the vehicle profile under "Cancellation".