Changing an Exposure (Article ID 158)

If a player inadvertently exposes the wrong tiles or exposes too many jokers, they can add to or take away from the current exposure as long as they have not discarded. After a player has discarded, exposures on their rack cannot be changed.

Order of Exposures (Article ID 83)

Although there is no rule about placing exposures in the hand’s order on the card, it is courteous to do so and put Jokers in the proper place.