Heh, I'm just writing this up for a talk later in the year (among other "Laws you need to know - the Director can't help you"). Cutting out the explanations: You Misbid Assuming it’s truly a misbid, then: The opponents are entitled to your agreement. They got your agreement. It’s not what you have, but there is nothing to correct, ever. But if it’s a misbid partner’s seen often enough to have a feeling, your agreement actually is “<agreement>, but I forget.” and the opponents are entitled to that. You may not say or do anything that could possibly wake up partner, outside of your bids and plays. This includes calling the Director and asking to speak with her away from the table. You may not use partner’s Alert, explanation or lack of Alert to “wake up”. You can’t bid in such a way as to try to wake up partner. You can’t bid an a way to “hope to survive”, for instance by passing a bid that would have been forcing if partner had explained the way you thought you were playing. Repeat: you do not have to do anything, even admit to your mistake (except to the Director). The opponents will likely call the Director, but that’s fine. If they have an issue and gripe at you, you can and should call the Director. Partner Misexplained The opponents do not have your agreement, so you must correct the explanation, at the appropriate time. You must not do anything (flinch, “No!”, …) before that time. You have to know the correct timing! If you or partner is declarer, you must correct the explanation before the opening lead. If the opponents are declaring, you may not correct the explanation before the end of the hand. It is likely that it’s going to be found out before then, of course. You still must bid and play as if partner explained everything correctly. This includes Alerting and explaining partner’s calls according to your agreements (even if it wakes partner up). Note that doubts go the way of “partner misinformed”. If you aren’t sure, after hearing partner’s explanation, that they were correct and you misbid, treat this as “partner got it wrong, not me”. You Misexplained It is rare, outside of “Clubs and a major - no wait, we play Brozel. Clubs and Hearts”. But it happens. You are required to correct your misexplanation no later than the end of the auction, before the opening lead. You are allowed to do so at any time. If you only wake up in the play, you must still correct it immediately. While “The Director should be summoned when attention is drawn to an irregularity” in general, it’s almost essential to do it when correcting your own explanation. For the Legal of all of this, read Laws 75 and 21, and Law 73 on Unauthorized Information.