67. 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.
68. 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 redouble 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.