Have your calendar of conflicts up-to-date and in your possession at auditions. Clearly stating your conflicts up front is the professional way to deal with this issue. Calling in after being offered a role, with major performance conflicts is unacceptable and unprofessional.
Created by a longtime talent agent, who was fed up with all of the wasted time, money and heartache expended by ill-prepared "newbies." You'll laugh, you'll sigh and you'll be forever grateful.