You can delete all the information by using the
Clear and Start Over option in TurboTax Online as long as you have not
already paid or registered. This will delete the information that you have
entered so that you can start over.
You could also set up another account using the same email address. See the TurboTax FAQ below on how to start another return.
https://ttlc.intuit.com/replies/4248526
https://ttlc.intuit.com/replies/3288574