Can I edit Turbo Tax to see what might happen by putting more into retirement for 2017? I have already filed the 2016 forms.

[ris]

We now have no mortgage, are renting, but want to put a lot more into retirement. I'd like to see the impact on taxes by doing so.

[Carl]

Do not under any circumstances make ANY changes to your already e-filed tax return. If you do, you will have major issues next year. Guaranteed.

Instead, create a new online account and use that account as your "toy" for this. Simply log out of the account you're using right now. Then below the password field click the "create account" link and go from there.