If you don't need all of the features of TurboTax Self Employed, you can downgrade from TurboTax Self Employed to another version of TurboTax Online, as long as you haven't paid yet (or registered in a free version) - but please bear in mind that you will need to clear any data which you have entered, and start over in the other TurboTax version. This is the only available method to downgrade versions.
Please see the following TurboTax FAQ, "Can I switch to a lower-priced version of TurboTax Online?":
TurboTax has a useful comparison of the different features, benefits and fee structure associated with each TurboTax Online version, to help you determine which version is appropriate for your tax situation - please see below link:
https://turbotax.intuit.com/personal-taxes/compare/online/