How to change your return

Do not file another return for that year.

Wait for your notice of assessment before asking for changes to your return.

Generally you can ask for a change to a return for a tax year ending in any of the 10 previous calendar years. For example, a request made in 2016 must relate to the 2006 or a later tax year to be considered.


Log on to My Account.

Click Change my return.

You can ask for changes to your:

  •  current year return
  •  returns for the previous 9 years

By mail

Send both of the following to your tax centre:

  • a completed Form T1-ADJ, T1 Adjustment Request, or a signed letter giving details of your request (including the years of the returns to be changed), your social insurance number, your address, and a telephone number where we can call you during the day
  • all supporting documents for the change, including those for the original assessment, unless you have already sent them to us

Send your current year return separately from any request to change a return for another year.

Processing times

  • online, usually within 2 weeks
  • by mail, usually within 8 weeks 

It may take longer if:  

  • Your request is sent in spring or early summer
  • Your request needs more review
  • We have to contact you or your authorized representative for more information or documentation

When our review is done we will send you:

  • a notice of reassessment showing any changes to your return and
  • a letter explaining why we did not make the changes you asked for or if no changes were needed

To change your address, go to How to change your address.

Forms and publications

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