Mah Jongg In Error with a Verbal Declaration of Mah Jongg and no Exposures (Article ID 52)
Abstract: If a player declares mah jongg but has not exposed any of their tiles and no one has disturbed their hand, they may change their mind and continue playing without penalty.
Question from a player: What happens if I declare mah jongg in error but do not expose my tiles?
Answer from the NMJL: “If a player calls Mah Jongg in error and the mistake is rectified immediately, before the hand is exposed or before other players expose or disturb their hands, the game continues without penalty.”
Source: Mah Jongg Made Easy 2020 pages 16 #2
Other answers from the NMJL:
“If a player calls mah jongg in error and the mistake is rectified immediately before the hand is exposed and before any other player exposes or disturbs the hand, the game continues without any penalty.”
Sources for other answers: National Mah Jongg League Bulletin Q&A 1993 page 12 https://www.nationalmahjonggleague.org