You can update this information in the 'My Info' section. Sign in to your account. Click on 'Take Me to My Return'. Click on 'My Info' on the left. Click on the Edit button to the right of your name. Scroll down to ''A few other things we need to know''. The 2nd question is the one you want to change to NO.
You need to amend your return if you have already e-filed and been accepted.