I was wondering if anyone knew the answer to this. On Telecharge it says Sierra Boggess joins Phantom on January 21 but it also says Samantha Hill alternates with Sierra on Monday evenings. Since January 21 is a Monday I didn't know which actress would be in the role. I want to buy tickets but wanted to make sure it was Sierra I was seeing. Thanks for the help. Here's the page where the info came from: http://www.telecharge.com/Broadway/The-Phantom-of-the-Opera/Overview