How to change your tax return after filing

You filed you taxes, then realized that you made a mistake. You’re not alone. Discover the steps to follow to change your tax return after filing.

How to change your tax return after filing

First things first

Do not send in a second return for the same year.

  • Before asking for a change, wait to receive your notice of assessment from the government. Once you do, you’ll be able to place a change request.

Placing a change request

You can place a change request online or by mail. You can only make such a request for the last 10 calendar years.

To make a change request online

To make a change request online, you’ll need to log on to your account with the Canada Revenue Agency and select “Change a return.”

To make a change request by mail

To make a change request by mail, you’ll need to complete a T1-ADJ-T1 Adjustment Request form and remit it to your tax centre with any supporting documents that have not already been submitted.

  • Essentially, you’ll indicate on the form which line or lines were erroneous on the first return you submitted and the revenue office will adjust the total in consequence.

Your change request assessment

After filing, you’ll receive a notice of assessment demonstrating the changes made to your return and the impact it has on the final amount.

  • It’s also possible you'll receive a letter detailing why the change were not completed if the changes you requested were deemed unnecessary.

How long will the it take for the changes to be made?

  • If you filed online, your change request will take about two weeks to be processed.
  • If you filed by mail, your change request will take approximately eight weeks.

Change request steps and checklist

  • Make sure you’ve received your notice of assessment.
  • Have your supporting documents ready (only if they were omitted in the original tax return).
  • Make your change request online or by mail (do not send any other documents or another tax return).

It's that simple

That’s it. It’s probably simpler than you thought.

  • If you do need help filing a change request, make the request with the help of a professional.
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