If you have to attend a class other than your regular class, you must notify the instructor either by phone or talking directly at least one day before. Do not just leave a message on the phone or send an e-mail. Oversleeping is not regarded as an emergency. It is strongly recommended for you to take advantage of this opportunity to meet Japanese people and teachers, and learn about culture as well as practice speaking. It provides information on Japan-related events, educational opportunities, language exchange, etc.
Any teacher can sigh the form.