For some of us, the rush to get the annual tax return filed on time can sometimes result in sloppy mistakes. Or perhaps you simply forgot to include that extra income on the side or simply didn't get some crucial T5 slip from a financial institution (it happens, and more often than you think). Whatever the reason, there's a fairly simple way to correct your error.

The Canada Revenue Agency prefers that you do not file an amended income tax return if you've mistakenly omitted income or made some other mistake when filing. Instead, you should write to the Tax Centre where you filed your return, requesting a change along with an explanation and any additional material, such as T4 slips, T5 slips, and receipts.

The CRA also prefers that you include form T1-ADJ T1 Adjustment Request (available on CRA's website). Alternatively, you can simply go the CRA's website and make changes to your return through CRA's online ReFILE service.

When corresponding with the CRA, don't forget to include your Social Insurance Number or Identification Number. If you want to discuss your return or assessment in person, you may bring your own copy of the return and assessment to your Tax Services Office.

If you think the return you actually filed is necessary, you should get in touch with your Tax Services Office to arrange for them to obtain the file from the Tax Centre. In some cases this may take a fair amount of time.

If you have already received a Notice of Assessment (which I'll cover in a future article) and did not formally object to it within 90 days of its mailing date, or within one year of the due date of the Tl return to which the assessment relates, whichever is later, you are technically bound by it.

Happily, though, the CRA's current policy is that you can apply for a change going back 10 years (technically speaking this is under the so-called "fairness package" introduced in the early 1990s). But if you apply for a change within three years of your taxation year, the CRA will normally simply process your adjustment (exceptions may apply where your requested change involves permissive deductions, such as CCA, or if it is based on a recent court case in which the taxpayer was successful).

Despite these policies, if you discovered an error in your favour and reported it to the CRA, but the 90-day/one-year time limit will expire before a reassessment is received, you may wish to file a Notice of Objection to protect your rights.

Previously published in The Fund Library on May 2, 2019

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.