Yes, you can undo a Roth IRA conversion

If you convert a traditional IRA to a Roth but discover you’d be better off if you hadn’t converted, it’s possible to undo it. This may be beneficial if the conversion pushes you into a higher tax bracket, you expect your tax rate to go down or the account value has declined. Generally, if you extend your tax return, you have until Oct. 15 of the following year to undo a conversion. (For 2016 returns, the deadline is Oct. 16.) It may make sense to undo the conversion and then redo it. We can provide details on the rules and help you assess your options.