No need to "cancel"---just abandon the return. Nothing will happen to it. No one else has access and it will not be filed. If you did not register, pay or file, you can try to clear it.
CLEAR AND START OVER. (or....just clear it and do not start over)
https://ttlc.intuit.com/questions/2586254-how-do-i-clear-and-start-over
Did not receive any help from Turbo. They do not offer a phone number to contact them.
@mcp7635107 TurboTax provides "do-it-yourself" tax software -- or you can pay an extra fee to have help from a "Live" expert. You did not post your question from that "Live" software. Any user--even users of the Free Edition-- can post questions and receive help from this user forum. There have been no posts from your username except for the posts on Nov ember 3---after the filing deadline. And if you are using a paid version of the software, you can contact customer support.
Nevertheless, you say you filed using some other software, so you have nothing to worry about in regard to the return you did not complete using TT.