You can make changes to a printed return that you haven't mailed by following these steps:

• Login to your TurboTax Account 
• Scroll down to the bottom of your page and click on the blue box "Add a State" (You are not actually adding a state but this gets you to the correct menu)
• From here, you can click "Federal" from the left side of your screen and then change what you need to change
• Walk through the "File" section to reprint or E-File after you have made the necessary changes

Please comment below if you run into any issues following the above instructions.