If "Cancellation and Rescheduling" is allowed, then upon successful booking, the cancel and reschedule links is included in the email of the confirmed booking.
If the client is not seeing the option to cancel or reschedule a booking in the email then that means
the meeting host is not be allowing cancellation and rescheduling. In such cases, the client has to reach out to the host in order to cancel or reschedule a meeting.