it is possible but good luck finding a verizon employee that will change it for you.

That's true. In 2003 when I called in to activate a Motorola phone, they asked me if it was made to operate in Verizon Wireless, and I told them it was. They usually will know the ESN's of all phones that are made for their service. If there's an ESN that they don't recognize, many won't activate the phone. It's not like Cingular, T-Mobile, and numerous regional GSM carriers that use SIM cards, and if you have an unlocked phone, you can slip the SIM card into another carrier's phone and use it.