I have already filed my federal return using another website. Can I submit just my state returns through Turbotax?

[DanaB]

You won't be able to e-file your state return, you will have to print and mail it. You will need to re-create your federal return in the TurboTax software or TurboTax Online but don't file it. Then prepare and file your state return using TurboTax.  Also please be aware if you do not qualify for the Free Edition then you will need to pay for both federal and state returns, even though you won't be filing your federal.

Please see this FAQ for additional information: 

https://ttlc.intuit.com/replies/4232481