change the name of the RC menu item

hi ...
anybody know how to change the name of the RC menu item when I clicks the menu item ?

example:
I want change the name of "Light On" became the name "Light Off"

then how to change the checked of the RC menuitem when I clicks the menu item ?
from true to false

description of my script:

rcmenu rclighthelp
(
  menuitem lighton "Light On" checked:true

  on lighton picked do $.enabled = not $.enabled
)