In the dark blue header on the TurboTax screen there's an icon for "forms" to the right. That will give you access to view all the forms in your tax file. Click on Schedule M1M, and when it opens, right click on the amount for line 18, and it will give you a menu that will allow you to override the amount. To go back to the entry screens, the icon in the upper right corner has changed to step-by-step, and that will take you back to the entry screens.
