You would need to Clear and Start Over
Follow the steps below to do so:
1. Sign in to TurboTax Online and open your return by clicking the orange Take me to my return button.
2. With your screen maximized, click My Account (at the top of your screen toward the right) and select Clear & Start Over.
3. Answer Yes to Are you sure you want to clear your return?
4. After your entries have been cleared out, we'll prompt you to select a Turbo tax product so you can clear and start over from the very beginning.