it's all a question on finding the path to that variable. you problem sounds more like "retreiving" the variable than "sending". to send just say:
to retreive you need the path of that var (the "address" of the timeline where that variable was set).
_parent.tempvar <- means the variable tempvar is one clip below.
_parent._parent.tempvar <- means the variable tempvar is two clip below.
_level1.someMC.tempvar <- means the variable tempvar is in a MC with instance name "someMC" on _level1