Since TurboTax calculates various credits and deductions differently depending on marital status, you'll need to start a new return listing the correct status to single. According to the Canada Revenue Agency (CRA), once you have been married, you cannot go back to single status. You have to choose either: separated or divorced in your marital status.
Use your find tool at the top bar and search for: Marital Status --> then choose a status that best describes your situation, then add the date of change.
If none of the Marital statuses provided suits your current situation, then you have make sure to choose "single" if you have never been married before.
Make sure to update the CRA with your current marital status since TurboTax doesn't do the update on your behalf. Please check the link on how to update the CRA:
https://www.canada.ca/en/revenue-agency/services/child-family-benefits/update-your-marital-status-ca...
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