As long as you have not already paid for the state return or registered it in the Free Edition, you can delete it. You can use these steps to delete. 

• Log into your return, click orange Take me to my return button
• Click on State Taxes near top right and choose Your State Returns
• There should be a Delete button there on that page next to the Edit button.
• And then select Yes after clicking Delete

If you do not see the Delete or Edit button once you are on the Your State Returns screen, go here for other steps to do to get that deleted https://ttlc.intuit.com/questions/1900608

NOTE: Sometimes, you won't see the option to delete, just Edit and Start Over. This is because you either already paid for your state or registered your free version while that state was attached to your return.