Etiquette for a Joker Exchange (Article ID 37)
Abstract: Joker exchanges are done by first announcing it to the receiving player. The tile to be exchanged is then handed to the receiving player. It is recommended that a player not place the tile on the table or touch another player’s tiles.
Question from a player: What is the correct way to make a joker exchange?
Answer from the NMJL: “It is recommended that a player never touch another player’s tiles. The player should first announce that an exchange is to be made. The replacement tile should be handed to the player whose rack contains the joker and that player makes the exchange and hands the joker to the other player.”
Sources: Mah Jongg Made Easy 2020 page 23 #14, National Mah Jongg League Bulletin Q&A 2018 https://www.nationalmahjonggleague.org