Yes. The term is "convert" your IRA to a Roth.
There is no $ limit on how much you can convert (unlike the $6500 contribution
limit). A 2017 conversion had to be done by 12-31-17. Any conversion, you make
now, will be a 2018 conversions and get reported next year. "Recharacterize"
in tax lingo has a different meaning.
