How can I convince the principal to let me graduate?

I had gotten drunk on a school trip, which the teacher who was taking care of us found but he only found one can. He called the deputy and the deputy let me go because there was no evidence of me drinking. They called the principal to notify him and he suspended me from school but said I'll graduate, just not walk. What should I do to convince him? I'm willing to do community service or anything else to graduate. Plus, I have a clean record and haven't done anything wrong in school. What should I do? Please answer.