Updated July 28, 2026. Quick answer: You are permitted one switch from fixed amortization or annuitization to the required minimum distribution method without it counting as a modification. It is the only sanctioned change to a running schedule, and it exists for the falling-market case.
Why it exists
A fixed payment set before a market decline can consume an account far faster than intended. Without a permitted change the only options would be draining the account or busting the schedule and paying retroactive penalties. The one-time switch is the release valve.
What it does
Payments move from a fixed dollar amount to an annually recalculated one based on the current balance. In a fallen market that generally means a materially smaller payment — which is the point, though it also means less income.
Once. In one direction. You cannot switch back, and you cannot switch again. Use it when the account is genuinely under strain, not at the first uncomfortable quarter — and confirm the mechanics and documentation with a preparer before making the change, because executing it wrongly is itself a modification.
Plan for it before you need it
If you choose a fixed method, know at the outset that this is your only lever, and decide roughly what decline would trigger it. Deciding in the moment, in a falling market, is how people end up simply stopping payments instead.
Sources
IRC §72(t) (10% additional tax and its exceptions); IRC §72(t)(2)(A)(iv) (substantially equal periodic payments); IRC §72(t)(2)(A)(v) (separation from service at 55); Rev. Rul. 2002-62; Notice 2022-6. Cross-checked July 2026 against professional analyses. Interest rates published for these calculations change monthly and are described structurally here rather than quoted.
This states what the cited authority says. It is not tax advice, and a SEPP schedule is unusually unforgiving of small errors.