Question: What happens if during the Charleston all players want to do a Blind Pass?

Answer: On occasion, all players might want to do a blind pass during the Charleston. If this occurs, the process is done with what is called an IOU beginning with East.  For example, East has one tile to pass, the other players have two tiles to pass. East passes one tile and says, “I owe you two more.” The player to their right is able to pass one blind, to their player on their left, and so on.  When East gets their full pass from the player on their left, they fulfill their IOU of two tiles to the player on their right.

Source: Mah Jongg Made Easy (2020, pg 13)