Certainly, you can keep your customers updated on the appointment changes via email notification.

Before approving or rescheduling an appointment, please:

2. In appointment detail > click Reschedule all > change the date and time of the appointment

3. Put a tick to checkbox Send email notification to the customers

4. Click Save

After the admin makes changes to the appointment, customers will receive an email about it. 

Note: the function only works when you reschedule all attendants of an appointment, not for each individual