You will need to change that Employer State ID number where you entered your Form W-2 (in the federal taxes part of the program). If you have already submitted your return, then you cannot go back and change it.
To get to your Form W-2s, you can enter W-2 in the search box at the top right of your screen and select "Jump to Form W-2". You can then return to edit the Form W-2 in question.
