Does anyone know how to change the answer about the retirement plan? I accidentally pressed yes and now it will not let me change the answer.

If the question you're referring to is, Is the IRA/SEP/SIMPLE box on this 1099-R checked?.

You can go back into the entry screen.  The box will now have been checked for IRA/SIMPLE/SEP box is checked . You can now Uncheck it.

This is how to post a 1099-R

1. Login to your TurboTax Account 
2. Click "Wages & Income" on the top
3. Scroll down to  "IRA, 401(k), Pension Plan Withdrawals (1099-R)" 
4. Answer "Yes" to the question "Did You Have Any of These Types of Income?"
5. Click "I'll Type it Myself"
6. Choose "Form 1099-R, Withdrawal of Money from 401(k) Retirement Plans, Pensions, IRAs, etc."
7. Click "Continue"
8. From here TurboTax will walk you through entering your Form 1099-R