This is a pretty common scenario, unfortunately - and if not handled well, could put you in a difficult situation.
Immediately after this individual told you she was unhappy with her current agent, you should have said something like, "Sorry to hear that, but since you have a contract with this other agent, I'm bound by the ethics of my profession to not talk with you further about this." And then change the subject, and do not engage any further in discussion... not even just listening to her complaints. By listening, you're tacitly condoning her behaviors and comments.
You can certainly say something like "I know you aren't aware of how agents are required to conduct business; after all, you're not a broker, so how would you know?". The point is to extricate yourself from a difficult conversation without giving her the opportunity to feel badly... or to continue complaining. (You want to hold yourself up as a professional, but not as someone who's ready to "punish" her for saying something that puts you in an uncomfortable situation.)
Don't run like a scared rabbit, though, as that could have made her feel like she's done something wrong.
As pointed out previously on here, she could be one of those people who badmouths everyone, and you may be very lucky she's under contract with someone else... so don't even daydream about the one that got away!
Linda - Mon Jun 29 2009, 12:32