When searching, remember, a few words are better than many
ID33-No Limit on Joker Exchanges
Question: Can I exchange more than one Joker during my turn or do I have to do one and wait for my next turn to do the other?
Answer: Once a player has begun their turn by picking a tile from the wall, they may exchange as many Jokers as they can from either their own rack or another player’s rack.
Source: Mah Jongg Made Easy page 24 #16