70. If, after the cards have been dealt, and before the trump declaration
has been finally determined, any player exposes a card from his hand, the
adversary {252} on his left may demand a new deal. If the deal is allowed
to stand, the exposed card may be picked up, and cannot be called.
71. If, after the final declaration has been accepted, and before a card is
led, the partner of the player who has to lead to the first trick exposes a
card from his hand, the declarer may, instead of calling the card, require
the leader not to lead the suit of the exposed card.