You can either choose to start from scratch by using the Clear and Start Over feature. Or you can navigate back to the beginning of the return to go through the return again.
To start at the beginning of your tax return please follow the steps below.
1) Sign into TurboTax Online
2) Continue your return by click Taxes > Tax Timeline > Take me to my return.
3) Once you are in your return click on the Personal Info tab. This is the beginning of the return. You may walk back through each section of TurboTax until you are ready to file.
Clear and Start Over TurboTax FAQ: https://ttlc.intuit.com/replies/4248526