If you want to renew your study permit or extend your stay in Canada as a student, you have to complete the Application to Change Conditions . First of all, check the expiry date on your study permit, and ensure you submit an application before that expiry of your previous visa. Keep in mind that you should submit an application for renewal at least 30 days prior to your current study permit expires.
In case you submit an application for a renewal or extension of your study permit and the permit expires before you take delivery of an answer, you can carry on to study in Canada under the similar conditions until you receive a result.
You should submit an application to renew or extend your study permit if you plan to travel outside Canada and your study permit will expire at the same time as you are travelling.
Note: You cannot renew or extend your student visa beyond the expiry date on your passport.
If your student visa has expired, and you have not applied for a renewal, you have to leave Canada.
Restoring your Student status in Canada
In a number of cases, you may submit an application to reinstate your status as a student in 90 days of losing it. You might only submit an application if you have sustained to meet the requirements under which you were allowable to enter and stay in Canada and you have met the entire conditions obligatory on your permit.
After you submit an application to reinstate your status, you might stay in Canada until a conclusion is made on your application but you are not permissible to study until your student status has been restored.