After the change to the program end date is made in the student's SEVIS record, the new Form I-20 is issued to the student. The program end date on the Form I-20 need not coincide with the graduation date. Rather, it is the end date of the student's enrollment in courses. It is not possible to extend the program end date simply in order to be able to stay around till the graduation ceremony. If the graduation ceremony falls outside the 60-day grace period of completion of coursework, then the student must find some other way to be legally present for it (for instance, by staying around on Optional Practical Training, or getting a B visa for the graduation ceremony). Whenever the student re-enters the United States after traveling, the student must have all of these at the time of arrival at the port of entry:   Since travel signatures are valid for only a year, students need to periodically get updated travel signatures on their I-20 from their international student office. The purpose of this requirement is to avoid cases where people who are no longer enrolled as students at an institution keep using an outdated Form I-20 to get in. In particular, when adding a new travel signature to the OPT, it is the responsibility of the international student office to make sure that the student is still enrolled at the institution. In case the Form I-20 runs out of space for travel signatures, the international office may print out a new Form I-20 for the student. In the special case of automatic visa revalidation, whereby the student returns to the United States after a trip to Canada, Mexico, or a nearby island for at most 30 days, it is not necessary to have a valid visa at the time of re-entry. However, it is still necessary to have a valid Form I-20 and a travel signature. After completion of studies, a student has a 60-day grace period to depart the United States. It is not possible to "re-enter" the United States during this grace period, regardless of the validity of visa or travel signatures. This does give the student some time to change to another non-immigrant status if applicable. However, if the student is unable to successfully change status the student must nonetheless depart the United States. One way a student can continue to stay in the United States on student status after completion of studies is by being approved for post-completion Optional Practical Training. Post-completion OPT can start at most 60 days after the completion of studies, and requires the student to work at least 20 hours a week (excluding up to 90 days of unemployment) on topics related to the student's program of study.