In TurboTax Online, you can't Clear & Start Over after you've registered.
If it's convenient, consider opening a new account under a new username. Up to 5 accounts can be tied to the same email address.
Here are the steps to create another TurboTax Online account:
https://ttlc.intuit.com/replies/3288574
Want to delete account? See this FAQ to contact Product Support for nine digit case number:
https://ttlc.intuit.com/replies/3300041
See this FAQ for Account Deactivation after getting nine digit case number from Product Support
https://ttlc.intuit.com/replies/4858329
