In order to do that you must submit a Case Specific Enquiry (CSE) attaching the document you wish to update along with an explanation of why and what you are submitting.
Here's the link: https://secure.cic.gc.ca/enquiries-renseignements/canada-case-cas-eng.aspx
Unfortunately there's no guarantee of anything with CIC... I can only tell you from my personal experience and some members of this forum. I have submitted two CSE so far, the first one got acknowledged and CIC emailed me confirming that the document was attached to my application I have not heard anything from the second one though.
They do specify that it may take up to 30 days for them to reply to a CSE and some members have reported waiting over 45 days... some never got a response at all. So as you can see, it is a matter of "luck" I am afraid. Give it a try anyways, better be safe than sorry!