If you have not mailed your forms, you can indeed
to back and make changes to the original return.
Please go back to Turbo Tax and click that you need to either amend your return or to add a state. You do not actually need to complete either of those, but if you select one it will open your return back up for editing.
Go to the top
Click on the Personal Info tab
Scroll down to Mailing Address and click Edit
Make the changes and click Continue to save the information.