Go straight to the principal, a principal. Then find the vice principal and the academic affairs office so as not to have individual leaders to protect the teacher. As everyone knows, protecting him will not be so easy. Don't look for the academic affairs office yet; The academic affairs office will try its best to suppress this matter for its own political achievements. Don't let the whole school know yet, so that the school leaders are very passive. It's really not possible to let the whole school know.
At the same time, you can sign the application and pay attention to the wording of the letter, which is well-founded and reasonable.