You can downgrade using the Clear and Start Over feature but bear in mind that the different TurboTax "flavors" handle different tax situations and their associated forms. Here is a short list of some common tax situations and the online products that now uniquely support them:
· Itemized Deductions (Schedule A/1040)- Deluxe, Premier, Self-Employed, and TurboTax Live
· Capital Gains or Losses (Schedule D) - Premier, Self-Employed, and TurboTax Live
· Rental Income (Schedule E) - Premier, Self-Employed, and TurboTax Live
· Profit or Loss from Business (Schedules C-EZ and C) - Self-Employed and TurboTax Live
Keep in mind that TurboTax Free Edition is intended for taxpayers with simple returns (1040EZ or 1040A with the standard deduction), e.g. first-time filers and students.
Please see the below information for downgrading to a different TurboTax Product:
https://ttlc.intuit.com/replies/3288495
Unfortunately, in order to downgrade from Premium, you will need to clear and start over. Follow these steps. This page will give you a little more information on switching to a lower version.