[quantumed]

If declarer misclaims for -1 when contract is making (all his remaining cards are good but he cannot remember), and both defenders have agreed (mistaken but assume they are unintentional), is declarer allowed to change it back if he realizes it was wrong? If timing is important assume he notices it the next day.

[pclayton]

In a nutshell, yes. You can't concede tricks that are impossible (impractical?) to lose.

[inquiry]

In main room on the BBO once the result is accepted, there is no way to change. In real world tournament, and in BBO tournaments with directors who follow the rules of bridge, phil is 100% correct.

[paulg]

In real life there is normally a correction period that is specified in the conditions of contest.

In my experience at club level this will often be a week (that is, until the same group/club meets again). In tournaments it will often be 30 minutes after the results are posted.

Paul

[barmar]

Law 71 says that the Director shall cancel such a concession within the "correction period", which is defined in Law 79C. 79C says that the correction period ends 30 minutes after scores are posted, unless the SO specified a later time.