Most taxpayers who want to look at the what-ifs open another Turbo Tax account and then enter everything in and play around with the system. That way there isn't any chance that something could happen to your original return that you cannot undo.
Instead, please follow these steps: 1.
Make sure you have signed out of your TurboTax account 2. Go to https://turbotax.intuit.com/personal-taxes/compare/online/ to
select the TurboTax product that will meet the needs of the filer 3. Create
their account, set up a new login for the additional return (you can use your
email address for up to 5 accounts if you want to receive e-file
notifications)