Previews

This may come off as a dumb question, but you guys alwasy seem to clarify all my questions...how do the previews work? Does the show rehearse during the day or how do they integrate the changes? If so, isn't that a really long day, rehearse in the morning, performance at night? Thanks.

----> Also, while i'm at it, Does anyoen know why the I SING Cd cost so much? Is it a two cd set? Thanks.

Once the show is finished it's frozen.