If you have already started with a upgraded version, you will need to Clear and Start Over. Keep in mind that the different TurboTax "flavors" handle different tax situations and their associated forms.
For example, if you got upgraded to Deluxe because you're itemizing (Schedule A), you can clear and start over in Free Edition, but as soon as you've entered sufficient itemized deductions to exceed your standard deduction, you'll be asked to upgrade to Deluxe again.
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