If you haven't paid for your TurboTax Online return yet, you can just delete it. 

To start a new return, select “Start a New Return” from under “My Returns” in the bottom left corner. Once you have started your new return, you can select “View All Returns” from under “My Returns”. Then delete the unwanted return by clicking the small Trash Can next to it or “Delete” under the return’s name.

You can buy TurboTax Desktop here: https://turbotax.intuit.ca/tax/software/desktop