Bookings can be deleted by clicking on the booking so it is highlighted.
Then click the  “Delete Booking” icon in the bottom  left corner 

A booking can also be deleted by right-clicking on the booking, and then Delete booking


Deleted bookings can be accessed in the deleted bookings menu at the top:


It is always possible to reverse deleted bookings back to active bookings. If moved to active bookings you will be asked for a manual reversal in case there is a conflict with bookings that were incurred after the deletion. It is also possible to see a log book on the details of the booking.
Use the icons at the bottom next to “New Booking”

How to delete a booking – Video guide