Maureen Anderman is her understudy. I have not heard of May missing a performance. While most roles on Broadway are "draining" to some degree, there are a few scenes where the character is offstage and each act is under an hour, so it's not like it's some epic one-person show.
Just remembering you've had an "and"
When you're back to "or"
Makes the "or" mean more than it did before