Go to My Account > Save and Sign Out. TurboTax will automatically save your progress and you will be able to return to complete preparation when you are ready. Make note of your username so you make sure you log into the correct account when you return. Also, you may want to look into an extension if you feel you won't be able to complete the return by the due date because of the incorrect form. The extension process isn't currently open on TurboTax, but it will be shortly. You can find more information at the link below.
https://turbotax.intuit.com/irs-tax-extensions/
Also, since prices for TurboTax products are about to go up in a few days, you might want to look into paying for the product now so you can lock in current pricing. You can get to the File tab (after State taxes and Review) and click Step 1 to pay for the product now.
