Yes, it will affect your original file as you have made changes to your original filed return. We hope that you have saved a copy of your return that you originally submitted.

If you still wish to delete a return, as long as you have not submitted that refile, it will not be transmitted to CRA. If you wish to "delete" the Refile you began in error, once you start or open another return in your online TurboTax account, you should see a little garbage can next to the Refile, and you can delete that file.

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Why would it affect my original return if I haven't submitted the ReFILE? I started it, but then decided I don't want to proceed with it. So it's still in progress. My original return has been filed. 

As long as you are not submitting it, the file will stay there. If you just want to delete the return you are currently working on, and you have other returns in your account, select “View All Tax Returns” from under “My Returns” and delete the unwanted return by clicking the small trash can next to it (or “Delete” under the return name). If there is no trash can next to the return that you want to delete, then open another return. Now when you go back to “My Returns,” you should be able to delete the unwanted return.