Yes, you can always upgrade to a higher version or Turbo Tax will make you upgrade if you try to enter something your version doesn't cover. If you want to go back to a lower version like the Free Edition you will need to clear and start over.
To go back to a lower version or the Free Edition you can try to clear and start over https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-online/00/26444
If you started your tax return in TurboTax Free Edition (Form 1040 with limited credits; roughly 37% of taxpayers qualify), you won't need to clear and start over. You can select Switch to Free Edition instead.
In the Turbo Tax Free Edition, information that you can enter is limited now. Why do I have to upgrade from the Free Edition?
https://ttlc.intuit.com/community/upgrading/help/why-do-i-have-to-upgrade-from-free-edition/00/26379
Or try the IRS Free File program
https://www.irs.gov/filing/free-file-do-your-federal-taxes-for-free