If a visitor, worker, or student loses their status in Canada, then they may apply to restore their status. Such applications are referred to as "restoration applications."
Restoration applications should be submitted within the 90-day period after their temporary resident status expires. The failure to do so will automatically result in the restoration application being refused.
For those who lose status because IRCC refused their temporary residence extension application, the 90-day window to apply for restoration starts on the date that IRCC refuses the extension application, rather than the day that the applicant receives the decision.
Finally, it is important to note that students cannot study during the restoration period, and foreign workers cannot work.