If you're not able to make it, you're welcome to cancel the reservation. Be sure to send a quick note to the student to explain why.
If you cancel multiple reservations in a row, however, the system will consider your schedule outdated and may clear it automatically. This is the only "penalty" incurred for cancelling reservations. You can re-update your schedule at any time.
Note: if you feel that a student can chat on Cambly respectfully but you'd rather not work with them, please let us know by submitting a request and explaining the circumstances. We can block the student from being able to see, message, or make reservations with just you.