How Do I Change My Tax Return?

Marin Perez

If you need to change your tax return, you can do so once you receive your notice of assessment. The best way to do it is through My Account online, but you can also send in a form or write a letter of request to your nearest tax centre.

Why would I need to change a tax return?

The CRA form used to make changes identifies the four most common reasons people request an adjustment:

  • You received an amended slip
  • You received a slip late
  • The CRA's published information was not clear
  • You did not know you could make the claim you are requesting to apply

You can check a box beside each of the above, and there's also a box for "Other." You can attach an extra sheet for additional explanation.

Which form do I need to request an adjustment?

You can request a change using the T1 Adjustment Request Form. In order to make a change to your tax return, it's important to have supporting documents available.  You will need to provide your social security number and the tax year to which the adjustment applies. An authorized representative can fill out the form on your behalf.  If a representative fills out the T1 form, you should provide a signed letter of authorization. Alternatively, the representative should have Level 2 authorization on the T1013 Authorizing or Cancelling a Representative Form.  Level 2 authorization grants a representative the right to change information such as income, deductions, non-refundable tax credits, and accounting transfers.  You would need to provide the precise line number from the return or schedule for each change requested (the form has space for four):

Download MileIQ to start tracking your drives

Get started
  • Your previous amount
  • The amount of change
  • Report the revised amounts
  • File your supporting documents along with the form.

When am I not allowed to change my return?

You can make changes to returns filed in any of the 10 previous years. If you want to change a return filed for the current year, wait until after your assessment comes.  If filing the request through My Account, you cannot use Change my return if:

  • The return has not been assessed
  • Nine reassessments already exist for the tax year to which it applies
  • It involves a bankruptcy return
  • It applies to a return filed before bankruptcy
  • Carryback amounts such as capital or non-capital losses
  • The return belongs to an international or non-resident client
  • It involves the elected split-pension amount
  • It involves income from a business outside your province or territory of residence.

What can I expect after filing an adjustment request?

The CRA advises that their inventory levels are "higher than usual," and that a T1 Adjustment request can take a while to process.  That being said, the CRA states that, once they have conducted their review, a notice of reassessment reflecting your request(s) will be sent. You would also receive a letter explaining the results of the review. Expect additional delays if supporting documents are not included with the request.