Question: Can a bettor communicate with the players during a game? Can a bettor change their bet once a game has started?

Answer: No, it is strictly prohibited for a bettor to engage in any form of communication or interference during an ongoing game. Once a bet is placed, it cannot be modified or changed in any way. If a bettor engages in activities such as discussing a player’s hand, revealing their betting choices, or making comments on a player’s hand during the game, their bet will be canceled.  As a consequence, the bettor is required to pay the appropriate amount to the winner at the end of the game.

Sources: Mah Jongg Made Easy (2020 page 24, #1, #2,#3, page 25 #10)