http://www.cic.gc.ca/english/information/applications/guides/5196E6.asp
Unless notified otherwise, advise us immediately, by mail at the address above or facsimile (905 803-7392) if, following the submission of your application, there are any changes to your family status such as marriage, divorce, births, deaths, your address, telephone or fax number, or any other important information. When advising the office of such changes, you must clearly state your file number, which will be found at the top of any correspondence we will send you to acknowledge the receipt of your application.
Unless notified otherwise, advise us immediately, by mail at the address above or facsimile (905 803-7392) if, following the submission of your application, there are any changes to your family status such as marriage, divorce, births, deaths, your address, telephone or fax number, or any other important information. When advising the office of such changes, you must clearly state your file number, which will be found at the top of any correspondence we will send you to acknowledge the receipt of your application.