Can I book an earlier appointment for my Non-B visa processing after my cancellation letter dates September 20?

The user is inquiring if they can schedule an appointment for the processing of their new Non-B visa before the cancellation date mentioned in their cancellation letter from the previous school, which is set for September 20. A commenter advises that it's typically acceptable to cancel a work extension 1-2 weeks prior to the date on the letter, but it's best to confirm with the immigration office.