The act of instigating a plan involving another person, but failing to follow through or notify the other person that you weren't coming.
The important difference between a chante and a flake is that to chante a person implies that you were the one that extended the invitation, and then subsequently bailed on the plan.
Although I havent heard the term used commonly outside of Washington, it seems to be gaining popularity over the last year.
Nick: No, she totally chanted me! Not even a courtesy call the next day to apologize or explain why she didnt call.
Man: Aw dude, I met this amazing girl who blew my mind. She was so radical dude. She had me totally stoked. Until I lifted up my arm to wrap it around her.
Dude: What happened man?
Man: She got this funky look on her face and scooted away from me saying that I smelled like something between freshly cut onions and dirty ass. Worst thing is she totally announced it to like everyone man.
Dude: Hahaha! Sounds like you ran into a Chante'.