Until 2018, there was a button.
You could convert $100,000 to a Roth in January, watch the market fall thirty percent by October, and simply undo the whole thing. Unwind it. Pretend it never happened. Pay no tax on a conversion that had turned out badly.
It was called recharacterization, and for conversions it was one of the great free options in the tax code. Heads you win, tails you take it back.
People built entire strategies around it. Convert several accounts into separate Roth IRAs, watch which ones performed, keep the winners and unwind the losers. A risk-free lottery ticket, run annually.
Congress noticed.
The Tax Cuts and Jobs Act eliminated recharacterization of Roth conversions. Since 2018, a conversion is permanent the moment you make it.
So the answer to the question in the title is short and unwelcome.
No. You cannot reverse a Roth conversion.
But that short answer hides three things worth knowing. One thing you can still reverse. One thing people confuse it with. And a set of techniques that replace the safety net you no longer have.
That last part is where the money is.