According to the release, Madonna has been put on "complete vocal rest" for 36 hours, on doctor's orders, and she regrets any inconvenience to her fans.
Tickets for the October 20 show will be refunded at the point of purchase. Tickets purchased online will refunded directly.
The show on Sunday, October 21, is expected to go on, and there are a "very limited number of seats" still available.
Where is she resting those vocals? The Granada Theater posted on its Facebook page that she was rumored to be "occupying three floors" at an unspecified Dallas hotel all week.
Once upon a time, that would've been an automatic Mansion on Turtle Creek, but these days, there's a lot more competition. The Ritz-Carlton, Dallas, maybe? One commenter on the Granada page speculated that it was the W Hotel; another pointed out that while in Phoenix, Arizona, she took up three floors of the Palomar.