If you have already filed, you cannot cancel it.
You cannot delete the account. However, you can clear the information.
In TurboTax Online, you can do just that with the Clear & Start Over feature as long as you haven't paid or registered yet.
- Sign in to TurboTax Online and open your return by clicking the orange Take me to my return button.
- From the My Account dropdown menu, select Clear & Start Over.
- Answer Yes to Are you sure you want to clear your return?
- After your entries have been cleared out, we'll prompt you to select a TurboTax product so you can start over from the very beginning.
https://ttlc.intuit.com/questions/2586254-how-do-i-clear-and-start-over
Please refer to the above article on how to clear and start over.
