They need another person

"You where the last person to switch, we need someone else to swap before we can fix this" Jen said "And then the stone would be blue" Karl said "Jeez Karyn I think you lost a few I.Q. points when you became Karl" Jen snapped "When it's blue I can change back then you can, then the third person can." "I'm confused can you go over that again slower" Karl asked Jen just sighed. ----------- "OK I think I get it now" Karl said enthusiastically, "we need at least one more person, a boy, to work this new stone" "Finally" Jen said relived "So who?"