If your student didn't show up at the confirmed time, you can cancel the request.
Login to the request page, and click the request.
When you click "cancel", you can choose the reason "Student did not
show up at the confirmed time".
You can also choose a Cancellation Charge of 0%, 50% or 100%.
If you choose this reason, the student will not be able to write your review, but you will, on the
contrary, be able to write one for the student.