You won't be able to make changes to a return that you have NETFILED unless you are doing a ReFile. This TurboTax FAQ has more information on how to ReFILE your return: I've filed my tax return. Can I still make changes?

If you are doing a ReFile and it's still not letting you make your changes, please contact our phone support team at 1-888-829-8608 as they will be better able to assist you.