The best answer to this is, not yet! We do have plans to include a cancellation waitlist feature, but it's not yet available.
For now, here's an idea for a workaround that can help keep track of clients who would like to be booked for a certain date and time if there is a cancellation.
The first step would be to create a new staff profile named "Cancellation Waitlist" as a Support Staff role:
Adding Staff Who Are Not Service Providers
Creating a new support staff profile will ensure that the remaining steps of this workaround will not interfere with any other staff members' availability that you have on the schedule. Support staff profiles do not appear online either, so it will not cause any new information to appear publicly.
When a client contacts the business asking if they can be booked for a time that is already booked, blocked time can be added for the date and time requested by that client:
When creating the blocked time, choose "Cancellation Waitlist" as staff and the client's name should be entered as the Reason to keep track of who requested that time.
If the appointment scheduled for that date and time is canceled, you can then convert the blocked time into an appointment:
Converting Blocked Time to an Appointment
Once the blocked time is converted to an appointment, the client will receive a booking confirmation email and reminders based on your settings.
This workaround will allow you to keep clients front of mind who have requested to be added to the cancellation waitlist and will allow you to easily convert the date and time to an appointment for that client.