The package went out at 4:40. At 5:15 you reread it and the figure in the second paragraph came from the spreadsheet you abandoned on Tuesday. Or the tone is a register colder than you meant. Or — the expensive one — a sentence in there reads as a commitment to a date you cannot make.
You reviewed it. You confirmed it. It is delivered. The next ten minutes are the whole of your remaining control. (If you catch it before confirming, this is not a correction — that is what cancel_draft is for.)
Correct it before they act on it
A correction that lands before the recipient has done anything is administrative. One that lands after they have forwarded it, quoted your number in their own document, or moved a date on their calendar is a worse conversation: you are not fixing a fact, you are asking someone to undo work.
So the clock matters more than the wording. Send it as soon as you are sure, without waiting for the full explanation. "The date in my last message is wrong — it's the 4th, not the 14th. More shortly." beats a polished note an hour later. Seeing that the original was opened tells you nothing about whether it was acted on, so assume it was.
Same channel, same thread. A correction that arrives somewhere else leaves two half-versions of the truth in two places, and whoever reads the original next cannot know it was superseded.
Lead with the correction, not the story
The instinct after a mistake is to explain: how the draft was assembled, what you were looking at, why the wrong figure was plausible. Put none of that first. The recipient needs the correct information; the reason is a distant second.
Weak: "I wanted to flag something about the message I sent this morning. My assistant drafted it from an earlier version of the planning doc, and while I did review it…" Three sentences in and the reader still has nothing usable.
Better: "Correction to this morning's briefing: the launch date is 4 March, not 14 March. Everything else stands. That pulls the review window in by ten days, so if you blocked time on the 14th it needs to move."
What was wrong, what is right, what it changes. And be specific enough that they never have to reopen the original and compare — quote the wrong phrase if it is short. The vague version, "some of the numbers in that last message weren't right", leaves the reader distrusting all of them, which is worse than the original error. If several things are wrong, list them. A three-item list is not embarrassing; it is a correction someone can act on in one pass.
Three kinds of wrong, three different repairs
A wrong fact is the easy case. State it, correct it, say what it changes downstream. Three sentences.
A wrong tone cannot be fixed by asserting a tone. "That came out sharper than I meant" works. "I want to clarify that my intent was positive" does not — it asks the reader to re-read the original with your intentions attached, and nobody can do that. Say what you actually meant, in the register you meant it in, and let the second message be the one that stands.
An unintended commitment is the one that costs. Assume they took you at your word; that is what a clear commitment is for. Two honest moves: keep it, or withdraw it and put something real in its place — a different date, a smaller scope. What you may not do is quietly narrow the language and hope nobody notices. If the commitment carries contractual weight, that is a question for whoever advises you; the message correcting it still goes out today.
Own it without performing it
Under-owning: "there may have been an error in the version you received." Over-owning: four paragraphs of apology, which hands the recipient your feelings to manage on top of their rescheduled week. The middle is short and plain. "That was wrong, and I sent it. Here's the correct version." One sentence, then the useful content.
Do not blame the tool. "My AI got the date wrong" is not a defence, because you confirmed it, and confirming is the act of saying this is mine now. A drafting assistant and an approving human are one system, and you are the accountable half. If a stale document really was the root cause, that belongs at the end, attached to a change you are making.
Say what you're changing only if you are. A remediation promise that quietly lapses turns one wrong number into a credibility problem the second time.
Where the correction lands
In a plain inbox, a correction is a new message that may or may not thread, may or may not be read next to the original, and will not travel with the first message when someone forwards it next week.
On threaded correspondence, the correction goes out as another briefing on the same thread, so anyone opening it later reads both in order — the practical argument for keeping the exchange in one recoverable place. The record corrects itself instead of accumulating orphaned amendments in three inboxes.
There is no unsend, by design: the review before delivery is the undo. Completing the record is the only repair still available.
Write the correction yourself
A fluent draft of an apology reads like risk-managed language, and risk-managed language is what people write when they are hedging — precisely the impression you cannot afford here. The sender's note is the field built for your own words, and a correction typed by you carries the verbatim, human-authored label because a person actually sat down and wrote it.
Let your assistant do the rest: the revised context, the recalculated options, the corrected package. The sentence admitting the error is yours.
If you would rather corrections land attached to the thing they correct, connect your assistant.