In any case, these rockers are in their fifties (right?) and they sadly don't have their twenty year-old bodies anymore. It's probably best they canceled. You will be able to get a refund at your point-of-purchase.
If you can't think of anything else to do on Saturday night, check the listings - there are plenty of other choices. We might just end up at home, snuggled up on our couch, with a cup of hot tea and watching the show-that-actually-goes-on, Moulin Rouge. We are so trying not to get sick, again, before the holidays end.