Vernon Baker was an African-American soldier who was retroactively awarded the MOH in the 1990s after the Army went through and reconsidered the awarding of the Medal of Honor in light of accusations of discrimination during the decision-making process.
Dr. Mary Walker was awarded the Medal of Honor (the first female) but it was taken away from her because she was a civilian contract surgeon and not an active member of the armed forces. Her award was given back to her in the 1970s.