Change of status for applicant in Canada
Different people apply for different type of visa to enter Canada. Once they are in Canada they can extend their stay or also apply for a Change of Status. The difference between Extension and Change of status is that, in extension you have valid ongoing visa which you want to extend in the same visa category. While in case of Change of status for the applicant in Canada, you might have particular visa or permit on ongoing basis but you would like to change that particular category of visa or permit to another one. To make it simple, if a person enters Canada on a visitor visa he/ she can continue to stay till validity of visa, he/she can also apply for extension before expiry of the present visa or permit. While if a person enters Canada on visitor visa and then later within validity of visitor visa applies for student visa or study permit then it is called a change of status.
In case if person fails to apply for extension or change of status within validity of present visa then he/she needs to apply for restoration within 90 days or else must leave Canada.