If your return has already been accepted by the IRS, then you will need to file an amended tax return for 2016. However, you will need to wait until your original return has been processed. Then, you will be able to file an amendment in the Turbo Tax software. You you will need to mail this return to the IRS, as this type of return cannot be e-filed. Please view the Turbo Tax FAQ below, for more information.
https://ttlc.intuit.com/replies/3288565
[edited, 02/04/17]