There are two ways to take a bay out of use, depending on how long you need.
Disable it from the bay settings
Disabling the bay from its settings takes it out of use for all future dates. Existing bookings stay in place, and the bay won't accept new bookings until you enable it again.
Block it for a set period
If you only need to close the bay for a specific window, a blocking is the better fit. A blocking lets you pick the exact dates and times the bay can't be booked. See What is a blocking.