First understand what is Study Permit: Visas and Permits
Remind that students and overseas workers apply for the first time to enter the study must remember to change Study Permit, see this: What if I forgot to change Study Permit?
But don’t think that changing to Study Permit is all right, as long as you are in Canada, remember to keep Study Permit effective! When you expire soon, be sure to remember to renew.

W, an MBA student at Brock University, I don’t know why the Student Visa was originally approved for only one year, so Study Permit is only one year, but the course is 16 months. It was found that Study Permit had expired more than a month after it failed. Fortunately, within 90 days of failure, we could make up for it, so we applied for identity recovery through MyCIC. The students are in very good condition, the results are all A, the overdue time is not long, and there is no other illegal behavior. We have passed an explanatory letter and hope that the visa clerk understands that it has not been renewed in time and approved the restoration of identity.

The application submitted on August 22, the letter of study was down on September 5, much faster than we expected. Our previous experience was that it took an average of three months, and according to the immigration law, it was impossible to learn before the identity restoration was approved. It is gratifying to approve so quickly that there is no delay in admission to September.

Finally, in Canada, you must keep Study Permit effective. To re-enter Canada, you must keep Student Visa valid.