I've since spoken with the agent who was showing and the potential buyers have rescheduled. The showing was scheduled through my agent yesterday, yet we were informed 20 minutes before the scheduled time today. I've also informed my agent that I'll be listing with another realtor due to her inability to communicate information that we should've had yesterday and the fact that this wasn't the first time it's happened. Had she informed us, the house would have been shown today and it wouldn't have been an issue. If I hire someone to do something, I expect them to do the job they were hired to do, or I'll find someone who will.