Out of the box, only members of the HOTELING ADMINISTRATION security group can cancel a Hoteling Booking with a Start Date in the past. This is desirable for regular, single day bookings. However, for multi-day/recurring bookings it is often necessary to cancel future date bookings sometime in the middle of the booking period. Right now it just won't let you. It should leave all past days as valid booking and cancel all future days to open the room for other bookings on those days.