Slander is the hard one. A post can be screenshotted; a remark in a hallway lives in the memory of whoever heard it. That is exactly why a slander cease and desist letter has to be more precise than a letter about a written statement, and why it should go out quickly, while the people who heard it still remember the words.
A false statement of fact, spoken to at least one other person, that harms your reputation. For most spoken statements you would have to prove special damages, an actual loss, like a lost job or contract. The exception is slander per se: a spoken statement that accuses you of a serious crime, injures you in your trade or profession, imputes a loathsome disease, or imputes serious sexual misconduct. For those, damages are presumed, and those are the statements a letter is built for. (The full comparison is in slander vs. libel in New York.)
The words. As close to verbatim as the listener can give you. "She told the board I'd been skimming from the reserve fund" is a letter; "she's been trashing me to the board" is not.
The listener. Slander needs a third party. The letter names who heard it, your manager, the co-op board on a specific date, a named client, because that is both the proof of publication and the audience a retraction must reach.
The date and place. The one-year clock under CPLR 215(3) runs from when the statement was made. Nail it down.
The demands. Stop making the statement; retract it in writing to the same people who heard it; preserve any notes, messages, or recordings. A slander letter demands a retraction to the audience, because there is nothing to delete.
Spoken defamation usually happens inside a relationship, a workplace, a building, an industry. The speaker often believes it will never be written down, never be traced, never matter. A letter from counsel that quotes their words back to them, names the listener, cites the per se category, and demands a written retraction converts a rumor into a documented legal matter. Most speakers stop. Some retract. The ones who keep going have now done so after written notice, which is the fact a court weighs most heavily on damages.
Statements are screened before anything drafts. Pure opinion ("he's hard to work with"), true statements, and speech on matters of public concern are not slander, and sending a letter over them can expose you under New York's anti-SLAPP law. If your statements don't support a letter, you'll be told so, with the fee credited toward any other letter or service.
The attorney-signed defamation cease and desist covers slander, libel, and online statements for one flat $499: screened first, drafted with the statute, signed by a New York attorney, and sent by mail and email within 48 hours with a proposed retraction the speaker can sign.
If no one else heard it, it isn't slander, publication to a third party is an element. If you were told about it secondhand, the person who told you is your witness; get their account in writing before sending anything.
The letter still does its job: from that date forward, any repetition is made after written notice. Your witness's written account, dated before the letter, is your evidence.
Recorded or broadcast statements are generally treated as libel in New York, which is better for you, damages are presumed and the evidence exists.
Yes, calmly and in writing, and keep a copy. A short factual correction to the audience is not defamation and it starts repairing the harm while the letter does its work.