BookingPress Waiting List Addon 

When any timeslot is fully booked, then Waitlist will allow the Customers to still book the appointment and try their luck for getting the service.

When any of the approved appointments Customer cancels or reschedule their appointment to another time, then the customers in the Waiting List can book and confirm their slots.

Easy for waitlisted customers to confirm their seats, as whenever the first customer cancels or reschedules the appointment, the particular seat will be displayed as available for the waitlisted customers, and an Email notification will be sent to all those customers, and the First confirming customer from the waitlist will be benefitted first unless another customer cancels or reschedules the appointment.

It also helps to save time and cost for your business, as one customer may cancel the appointment, but another customer can directly book the canceled appointment timeslot and keep the flow constant.

So, the cancellation will no more ruin the business, but will enlarge its Efficiency.