If you don't need self employed version of TurboTax 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 keep 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, for more information:
https://ttlc.intuit.com/replies/4248526
