Opening Lead Out Of Turn
This often happens. A defender sees the final contract, thinks they are on lead and plays a card, but partner is on lead.
It helps to make the opening lead face down, partner will stop you from facing the card and it can be withdrawn.
If the wrong defender makes a faced opening lead then Declarer has FIVE options :
A. Accept the incorrect lead and play on. Dummy goes down as normal, but the next card is played from Declarer's hand.
B. Accept the incorrect lead and have partner become Declarer. Your hand goes down as dummy and plays next.
Otherwise, we don't accept the lead and the lead reverts to the correct defender.
And now we deal with the incorrect lead as a major penalty card :
C. Demand the lead of the suit of the penalty card. The penalty card can be picked up and restored to the hand, and doesn't have to be played to this trick.
D. Forbid the lead of the suit of the penalty card. The penalty card can be picked up and restored to the hand. This prohibition may continue for as long as the non-offending defender remains on lead.
E. Allow any suit to be led. The illegal faced card remains a major penalty card, has to be played at the first legal opportunity, and lead restrictions can still be applied later.
North bids 1NT, South 3NT. East leads the 4 of hearts face up. West is meant to be on opening lead.
North has five options. They can accept the lead and just play on, South goes down as dummy, North plays next. They can accept the lead and put North down as dummy, South becomes Declarer and plays next.
Or they can not accept the lead and the 4 of hearts becomes a major penalty card. Now North can demand a heart lead, and the 4 gets picked up; forbid a heart lead and the 4 gets picked up (and continue to forbid a heart if West remains on lead); or allow West to make any lead and the 4 of hearts remains face up on the table.