Use "add a state" to get back in your return to make
corrections (before filing).
1. Sign In to TurboTax Online
2.
Click "My TurboTax" menu
3.
Press "Visit My Tax Timeline"
4.
Under the "SOME
THINGS YOU CAN DO" heading, choose "Add a
state" (you're not really adding a state, this allows you to get
back into your return).
5.
Complete/correct as needed.
If someone has already e-filed using one of your
social security numbers on your return, for security purposes, no other tax
return can be e-filed with that same social security number during that
filing season.
If you e-file with your son and you receive an error
message "already-filed
Social Security numbers" you
will need to paper file your return and not be able to e-file.
https://ttlc.intuit.com/replies/3302450