I am married and filing separately.I make $86,000and fully fund my 403b.Not knowing the rules, I fully funded my RothIRA .Can I convert the Roth into a Traditional IRA?

You can recharacterize the contribution. That will make it a Traditional IRA contribution, and you won't be penalized for that.

You then convert the balance in the Traditional IRA to a Roth.

1. You need to recharacterize the Roth contribution today. The Traditional IRA contribution will be on your 2016 tax return
2. If you decide to convert the Traditional IRA to a Roth, that will be reported on your 2017 return (you can't convert for 2016 in 2017)