Unfortunately, there is no way to downgrade a TurboTax product once it has been upgraded. You would need to create a new return and select the free version. Once you have started your new return, you can click on "View all tax returns" and click the small Trash Can next to the unwanted return to delete it.
If your daughter is 25 or under she can do her return no matter the version for free and it will show only when ready to pay as $0.
If she is not 25 please see our list below to see what a free simple return includes.