Reassign an appointment

I would love to be able to switch the staff conducting the appointment without having to cancel and rebook (we charge for bookings, so that would create a lot of client friction). To serve the client more effectively, when one of my staff members is running late and another finishes early, we take the next client instead of keeping the client waiting and having staff idle. My suggestion: on the appointment detail page, where the staff name is listed, there would be a dropdown menu showing the availability for that type of appointment.