If this was a Roth contribution made in 2015, then it would be entered on your 2015 tax return (the year in which the contribution was made), not 2016 when it was recharactorized. You had until the due date (or extension date) to recharacterize a 2015 contribution.
You may need to amend your 2015 return if that is what you are asking.
You enter a recharacterization into the IRA contribution interview as a Roth contribution and the interview will ask if you recharactorized to to a Traditional IRA and then ask for a explanation statement.
For a recharacterization of a contribution made for 2015, it's unnecessary to enter the code R 2016 Form 1099-R into 2016 TurboTax. In 2015 TurboTax, by indicating in the follow-up to entering the Roth IRA contribuiton that you recharacterized the contribution to a traditional IRA, the recharacterization would have been reported on your 2015 tax return with explanation. That's all the IRS needs. If you did not already report the recharacterization on your 2015 tax return, you'll need to amend your 2015 tax return as macuser_22 indicated.
Because all of the necessary information regarding a recharacterization is to be entered on the required explanation statements, TurboTax essentially ignores code N and code R Forms 1099-R. If you want to, you can enter the form for recordkeeping, but TurboTax will otherwise ignore the form.