I'm sorry, but the only way to downgrade your online product is by using the "Clear and Start Over" feature. And yes, your entries will be deleted. :(
https://ttlc.intuit.com/replies/3288495
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***