Dummy is not liable to the penalty for a revoke; and if he should revoke and the error be not discovered until the trick is turned and quitted, the trick stands good.
A card from the dealer's hand is not played until actually quitted; but should the dealer name or touch a card from the dummy hand, such card is considered as played, unless the dealer in touching the card or cards says, "I arrange," or words to that effect.
CARDS EXPOSED BEFORE PLAY
If, after the deal has been completed and before the trump declaration has been made, either the dealer or his partner expose a card from his hand, the eldest hand may, without consulting with his partner, claim a new deal.
If, after the deal has been completed and before a card is led, any player shall expose a card, his partner shall forfeit any right to double or re-double which he otherwise would have been entitled to exercise; and in case of a card being so exposed by the leader's partner, the dealer may either call the card or require the leader not to lead the suit of the exposed card.
CARDS EXPOSED DURING PLAY
All cards exposed by the dealer's adversaries are liable to be called, and such cards must be left face upward on the table.