Kwannon's body-switch with Betsy Braddock occured behind the scenes in Uncanny X-Men (1st series) #256. She first encountered her mirror-sister in X-Men (2nd series) #20. Her Legacy infection was revealed in X-Men Annual (2nd series) #2. Kwannon was mercy-killed by Matsu'o in X-Men (2nd series) #31.
After an encounter with Sapphire Styx in Death of Wolverine: Mystery in Madripoor #1-4, Betsy Braddock's Asian body died and was replaced by her original British body. As a side-effect, Kwannon seems to have somehow been resurrected in her original form as well. Because of the changes Kwannon's body has been through, she now possesses both the telepathic and telekinetic abilities Betsy had when she was last in that body.