If you have not e-filed or mailed your forms, you can indeed to back and make changes to the original return and not have to wait to amend.
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 and click on the Federal Taxes tab or State Taxes tab and this will open the federal return so you may add your information and then proceed back to the File tab.
Have you opted to have your return filed either electronically or by mail?
If you have not e-filed or mailed your forms, you can indeed to back and make changes to the original return and not have to wait to amend.
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 and click on the Federal Taxes tab or State Taxes tab and this will open the federal return so you may add your information and then proceed back to the File tab.