Originally Posted by
cbn42
Domestic is a different matter, but I don't know of any international airports in the world where you can clear outbound passport control and then turn around and leave. At the least, you would have to explain your situation to someone and get escorted out. The amount of resistance you face will vary.
I've done this at HKG and NRT a few times. I've never had to do anything more than tell some guard what I wanted to do to be let back into the arrivals hall (and, of course, go through entry immigration again). In NRT, you just go backwards through the transit security checkpoint. HKG is the same.
Immigration in both places gave me no issues either: a simple, "I changed plans because something came up with work" (which was true) sufficed in all cases, and I was happily stamped back in.