Updates are for the last couple of weeks:
Kristina Fernandez has replaced Maia Evwaraye-Griffin in the ensemble.
Bud Weber has replaced Constantine Rousouli in the ensemble.
Libby Servais has left the Broadway Company.
Tania Mathurin has replaced Aileen Donohoe as the Midwife and an understudy for Madame Morrible.
1st National Tour
Sarah Schenkkan has replaced Alli McGinnis in the ensemble and as an understudy for Glinda.
2nd National Tour
Paul Kreppel replaced Don Amendolia as The Wizard, on March 7, 2012.