What do you do when you’re scheduled to sing, and you have a sore throat? Do you reschedule your date to sing, or do you try to muster through and sing anyway? What if you’re scheduled to sing for an event that you can’t cancel? This is on my mind because I seem to be surrounded by sick musicians. It’s flu season. And, over the past month, at least half of the singers I work with have come down with the flu or some type of upper respiratory ailment. There’s more coughing and sneezing filling the stage than singing right now. For a singer…