How would an emergency cover for a role that one actor doesn't cover work?
Just as the title asks: how exactly does an emergency cover work if an understudy goes on for a role they haven't covered with very little to no rehearsal time? I'm asking this because tonight at Paddington, Rose Mary O’Reilly is currently making her emergency Millicent Clyde debut. O'Reilly is usually a swing and an understudy for Judy Brown and Millicent Clyde is a role she doesn't cover. So I'm curious to know how this would be pulled off effortlessly with a very limited rehearsal time.