Think of it like being stopped by the police. Be polite, answer all questions simply ("Yes, sir", "No, sir") and if they mess up or are wrong, that's a story to be told in court, not to them. You can't argue your way out of a traffic ticket with a police officer; you can anger him and make the situation worse. Save the argument for the courtroom, where it belongs.
If it's 1-on-1, you can ask questions and for direction about how to improve. You can point out gaps in her knowledge. It might not help, but it probably won't hurt. That said, the odds are strong that the decision has been made already. A mediocre review isn't a big deal (we've all had mediocre reviews from time to time; I know managers who give everyone mediocre reviews to protest the process.) However, the only time that a boss gives a negative formal review and doesn't intend to fire that person is when she's "storying" you — that is, depicting a strong performer (you) up as a straggler early on, with the intention of giving him fair reviews in the future in order to create a story of "rescuing" a low performer and thereby making the case for her own promotion. Being "storied" hurts your career — she won't take you with her when she gets promoted, and you'll be unable to transfer due to the stigma of the bad review — so the general advice of "get another job" still applies.
If it's with your boss and the CEO, do not say anything. I am serious: say as little as possible in a 2-on-1 meeting. If the silence makes them uncomfortable, that's their problem-- not yours. Be polite but convey no information. Answer any question with, "I'll have to think about that." If they want an immediate answer, say "I have to go to the bathroom" and get on the phone with a lawyer. Write any questions they ask down, and ask an employment lawyer how you should respond. If you're in a one-party-consent state (i.e. you can legally record a conversation without them knowing) then record the interaction on your phone. Saying anything at all in a 2-on-1 meeting about your performance is incredibly dangerous. Just don't do it. Remember that your boss is the CEO's employee and can be threatened with his job into corroborating any "official version of events" that they'd like. (Recording the interaction, if it's legal in your state, can help.) Subornation of perjury in these sorts of cases is extremely common and you have no witnesses on your side, while they have each other. You're in trouble if you say anything at all. Even if you have no intention of taking this to court, the fact that you might is an HR concern that will determine how much severance you get. If you said something stupid in a 2-on-1, you're likely to get zero. And there is little of substance that you can say that isn't stupid.
A negative performance review means you need to be looking for another job, plain and simple. You can try to put time on the clock, divulge health issues so you get a severance when the axe does fall (you can only put it off for so long), but you're basically already fired. Get another job. There's nothing you can say in the meeting that can help you, and there's a lot that you can say that will hurt you (being interpreted as insubordination, or even a threat), and if it's 2-on-1, they'll even be able to agree on a story (however false) that seals the deal in their attempt to fire you "for cause." Anything you say can and will be used against you. So say little to nothing in the meeting. "Smile and nod." (Actually, don't nod. You don't want to feign agreement. Be poker faced.) Refute any false claims about your performance later on, in writing, and make sure that you send a copy to your personal email account because, at this point, you can lose your work email account at any time.
This question originally appeared on Quora: Office politics: When sitting in a negative performance evaluation, should you defend yourself or just smile and nod?
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