what happens when a company leaves a stock exchange? (not delisting)

[nereo]

Hi

I've got a hypothetical question that I can't quite seem to find an answer to and can't quite wrap my head around.
I have some understanding of what happens when a stock becomes delisted by a stock exchange (its normally listed on over the counter boards while it goes through bankruptcy).
What I'm wondering though is what happens if a profitable company chooses to leave, say, the NYSE and join the LSE or the TYO? 
I'm asking because I can envision a time when multi-national companies that already do most of their business in a country other than their home company might want to switch their listing. 

Certainly this has happened before, right?  Maybe a company leaving the NYSE and joining the NASDAQ?  Is it just a matter of "changing the address" like someone might do if their work moved to a new office?  or is more involved than this?

[geekette]

Interesting question.  Companies do move between the exchanges here in the US.  At least one I know of was dual listed on the NYSE and the London exchange (and dropped the US listing a few years ago).

It's probably more involved for the company than for the investors.

[Spork]

With NYSE/foreign stocks, they're usually not really listed in both places (... or... as far as I know they aren't... correct me if/when I'm wrong.)   Usually they're ADRs.  It's sort of a stock IOU for a stock in another currency.

It seems like a similar thing for "a different stock exchange" would be possible as well, but I have no idea if it has actually been done.

[geekette]

You're right - I looked deeper and the company (Spirent) had ADRs on the NYSE.  That's what I get for reading nothing but headlines.  The only reason I knew anything about it was because we had friends there.