The IRS will start processing returns on Feb 12. Until then TurboTax will hold your pending e-filed return. Pending returns can not be changed. If the return is accepted you will get an email. If the return is rejected the e-mail will tell you what to correct and you can make changes before
e-filing again
.
Amend to change an accepted retur
n. Instructions below
.
https://ttlc.intuit.com/community/amending/help/how-to-amend-change-or-correct-a-return-you-already-filed/00/25588
You cannot unregister. Once you have submitted payment, deducted the TurboTax fee from your refund, or registered, you cannot erase your return and start from scratch in TurboTax Online.
Or if it doesn't let you clear and you haven't paid and filed you could just start a new account. Online is only good for 1 return per account. But you can use the same email address for 5 accounts. How to start another return in the Online version