Yes you have to inform them of any changes to your application, a change in employment qualifies as a change in your circumstances. On the AOR you should see this information
If your circumstances change you have to let us know. To notify CIC of changes to your application, visit www cic gc ca/english/information/offices/missions.asp
select the office that serves the country in which you are
living, and follow the directions for "Case Specific Enquiry."
The link was that useful when I clicked on it, so I would either call CIC or google the case specific form and submit this new information, but maybe others on this forum will be able to direct you to a specific way to submit case specific enquiries
