Last week, soprano Dawn Upshaw, who is famous for never cancelling engagements, cancelled an engagement with the Australian Chamber Orchestra, due to a vocal cord injury. It may be unusual for Upshaw to bail on an orchestra, but other soloists do it all the time, for any number of reasons. Some soloists are even as famous for their cancellations as they are for their performances. As for the jilted ensembles which are left to scramble for a replacement, many arts administrators pride themselves on their ability to come through in just such a situation.