Reschedule function not working correctly - doesn't remove original booking

Hi, I am using Bookings for my clients to choose slots. I have a pre-determined set of slots. I have had several instances in the last week of clients not turning up for their appointments . After enquiring they all said that they re-scheduled their exam using the 'reschedule' option in the confirmation email. I have checked and their new booking is showing in the calendar, but their original appointment is not removed. Could this be investigated/fixed? I am using Bookings for automation and to remove admin but this is causing me a lot of hassle and wasted time waiting for people to turn up when they won't because they have re-scheduled.