Law 15 - after play has started.
A situation from the tournament I am currently directing:
Bidding: E 1C, all pass.
S leads a small heart, dummy goes down and plays some heart, North plays AH.
At this point, E realises that both she and Dummy have 10C. It transpires that W has been bidding on the hand from the next board.
Law 15A1, W's pass is cancelled, as is N's pass.
Law 15A2b: W should pick up the correct hand and bid. The knowledge of N's withdrawn bid (and the withdrawn cards?) is AI to NS but UI to EW.
The thing is the play has already started. Law 15 says nothing about rectification only being possible during the auction period or before play starts.
Clearly if the play had advanced significantly it would be impossible to allow the board to play normally, but here the UI is small, and allowed to NS.
What should I do (and what in the laws guides me to this)?