"I don't understand the term "passing over" in the sense you've used it -"
John Edwards. Sylvia brown. Also in a good spiritualist church I know of. A speaker stands in front of the crowd and talks about the "invisible people" who came to talk to someone. Like my example of what happened to my Father.
Channelling is ultimately when the spirit lifts your spirit out of your body and places it somewhere on a park bech or somethign in the astral. Then uses your body to talk. JZ Knight and Sylvia Brown does this. They always don't have a clue what was said during the channel because they were not present.
Milder versions of this is when people "channel" entities ike the pleadeans or Ra or Toth, Kitumi , Tobias, or Abraham (Ester Hicks) Lizaris, Omni and chaneled teachers.
Your "passing over" is a term for what we just call 'platform mediumship'.
Your 'channelling' appears to be 'deep trance' mediumship...
The lighter form of channelling you mention would be mediumship for teaching and guidance - deep or fairly-deep trance to convey the words of spiritually evolved teachers, mostly on spiritual issues.
I forgot to say thank you - this has helped clarify a number of ongoing issues for me...