Here is information on how to clear and start over.  https://ttlc.intuit.com/replies/4248526

You are not able to clear and start over after you have paid, registered, or deducted the TurboTax fee from your refund.    

However, you are still able to make changes to the return as long as you have not e-filed or mailed it. 

1. If you don't see a toolbar, scroll to the bottom of the Home page.

2. Click Add a State (don't worry, we're not really going to add one, we just need to get to the right place).

3. On the left you should see a toolbar.

4. To make changes, click the Federal section.

5. Once changes are complete, continue all the way through the interview questions until you reach the File tab.

6. On this tab you will choose whether to e-file or mail your return.  IMPORTANT:  Once you press the e-file button or place the return in the mail, you will no longer be able to make changes to it.  Once the return is filed, you will have to do an amendment.