No one here or TurboTax can cancel your 2020 return.   Once you e-file a return, you cannot get it back, cancel it, or make any changes to it. 

If you need to make changes or add information, you will have to wait until your return gets accepted or rejected to make any changes.  Do not make any changes to your e-filed return, it will not go through.  The IRS is not accepting returns until Feb. 12th, you will have to wait until then to see if your return is accepted or rejected.

If rejected, you can enter or change your information, then re-e-file.

If accepted, you would have to amend your return to make changes or add information.

Also, the Federal amended return (1040X), will not be available until around Feb. 28th (subject to change).

@5_19  As stated above, no one here or TurboTax can cancel your return.  If you have not filed your return yet & you are using the Online version, you can use the Clear & Start Over option in TurboTax.  Then just abandon the account.

As long as you haven't submitted payment, deducted the TurboTax fee from your refund, or registered, you can erase your return and start from scratch in TurboTax Online.

How do I clear and start over in TurboTax Online?

https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-onli...

@Coffeeman750   As stated in the above posts, no one here can cancel your return.  You also cannot delete your account.  Since you did not file your return you can just abandon your account.  If you can you can use the Clear & Start over option to remove any information in your return.

As long as you haven't submitted payment, deducted the TurboTax fee from your refund, or registered, you can erase your return and start from scratch in TurboTax Online.

1. Sign in and select a topic to continue your return.
2. On the next screen, from the left-side menu, select Tax Tools, and then Clear & Start Over (select the menu icon in the upper-left corner if you don't see this menu).
3. Answer Yes in the pop-up to confirm.