Student or Learner
Is that AmE?
Context helps. Yes, sometimes some people refer to death as "passing over" into the next realm.
Exactly as Dave says - it would be used by people who believe the soul of the dead person goes to a different place. Anyone who thinks the dead person can communicate with them (i.e,. they are seeking the help of a medium) must believe the soul still exists somewhere, so they would be good candidates for this use. I do believe our soul goes somewhere else, but don't use this phrase.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
It's a sort of "New Age" expression and not one of the more traditional Christian beliefs. I'd never heard it used until maybe 10-15 years ago.
The phrase is often used in stage acts by mediums (or other people who claim to be able to communicate with the dead). In The Mentalist, Patrick Jane used to be a charlatan who had a stage show in which he claimed to speak to the dead, as of course you know if you're watching the show. If you have ever seen any of the broadcasts by John Edward or the funny little British guy whose name I have forgotten, you will hear "When did he pass over?" and "I'm getting a lady who passed over a few months ago" etc.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.