Sorry but this is going to be complicated. Once you have filed a completed income tax return, you cannot & must not try to submit another "corrected" return. The system will not accept it. You have to prepare a special form called "ADJUSTMENT REQUEST". T1ADJ is the form number. TurboTax has this form in its program. Click on the "FORMS" selection box & look for the ADJUSTMENT REQUEST or T1ADJ form. If you use the T1ADJ form that is already in your previously filed return, it will open with some of the required information, such as name, address etc already entered. The detailed instructions about how to complete this form are on the second page, along with the address of your tax center. When you have completed the ADJUSTMENT REQUEST form, you MUST MAIL IT, (Yes, MAIL IT), to your tax center. Under the section C, ADJUSTMENT DETAILS, enter the line number or the schedule name that you want to change. RRSP info is on schedule 7. Enter the information needed using the column names. They are quite understandable. Under "OTHER DETAILS or EXPLANATIONS", type in something like "Please amend my 2014 tax return to include the above change to my RRSP deduction" or something along those lines. Attach copies of ALL documents needed to backup your claim. NO RECEIPTS = NO ACTION! Make copies of everything you send to CRA. Be prepared, Adjustment Requests take several months to process, especially during tax season.