I need to amend my federal tax. I forgot to add a dependent.

If you already filed your federal return and it's been accepted, you can amend your 2016 return by following these steps:

1. Sign back in to TurboTax and go to your Tax Timeline.  [See Screenshot #1, below.]
2. In the section Some Things You Can Do (below the grey line), click on Amend (change) return. [Screenshot #2]
3. On the screen, Are you sure you'd like to amend, click the box Amend using TurboTax Online.
4. On the screen, Have you already filed this return, click the Yes button and then click the button next to I need to amend my 2016 return and click Continue.  [Screenshot #3 ]
5. On the screen, What do you need to change on your return, scroll down and click on the Update box next to the Personal Info & Dependents. [Screenshot #4]
6. When on the Personal Info Summary, click on the box Add a dependent.  [Screenshot #5]