Question: Is there a process to doing a Joker Exchange?

Answer: Joker exchanges can only be done during your turn. Here are the steps for proper etiquette during a Joker Exchange from another player’s rack:

1. Pick a tile from the wall or call a discard before performing your Joker Exchange.
2. Announce your Joker Exchange to the receiving player by asking politely, “May I have your Joker please?”
3. Hand your natural tile to the receiving player and let them hand the Joker back to you. This is often referred to as a “hand-to-hand” exchange. If a player does not announce their Joker exchange and the tile touches the table, it is considered a discard and the Joker can no longer be exchanged. 
4. If a Joker Exchange is done after calling a tile, the Joker cannot be used to complete the exposure. It must be put in the rack and used accordingly.

Sources:  Mah Jongg Made Easy 2024, pg. 24, #13 and page 19,(b)