I've searched this site and couldn't find the answer to this (maybe my search verbiage was inefficient)...
at any rate, if you unlock the phone, take it to asia use it there with a local SIM card, is there anything you need to do when you return to the U.S. to get your "regular" verizon service -- do you just remove the sim?
I don't think you even have to remove the sim card as that has no effect on the US frequencies the phone will use once in the US. You do need to UNlock it for non-verizon sims by calling verizon while a (any) sim card is inside the phone.
The only thing you might want to make sure of is that it is set to gsm mode in asia, and cdma when u come back stateside. as long as it is unlocked, you can put a sim in, turn it to gsm mode, then talk away. If you are overseas and find that it isnt unlocked, i know you can call verizon's global support and they can provide one. Just make sure your antenna settings are correct though. Good Luck