Once you have paid and submitted you will not be able to downgrade. You will be able to still fix your return and resubmit it, More information has been provided for you below.
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-onli...
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
