Got this here: https://ttlc.intuit.com/questions/3923162-can-a-person-modify-already-printed-returns-before-mailing...
Will copy and paste below. It worked for me, though I had to log out a couple times. It kept telling me I couldn't amend yet when clicking "Add State"...
Yes, if you have not yet e-filed or mailed the return, you can go back in and make changes before filing.
You can get back into your return using the steps here below:
- Log into your TurboTax account and click My TurboTax at the top
- You should be on the Tax Timeline now
- Scroll down to SOME THINGS YOU CAN DO section
- Click Add a state (not really adding one, just a way to get back into return)
- And make the changes you need to
