If you are using the VZW service with an international plan, a new sim card is not needed. It will use the same device, sim, phone number and setup that you have currently (aside from making sure roaming is turned on in "settings" so that it will use GSM networks while in other countries).
The only time you would need a new sim is if you are only using the phone, but not the Verizon service when travelling internationally which is generally used when staying in another country for an extended period of time (30 days or longer).... Most that go this route get a local Chinese (or local) number on a prepaid service while there, allowing them to use their same phone while there.
What an exciting trip you have planned, CYNSHO10! You made a great start asking for advice here. In addition to the suggestions offered by lukevinyl, I urge you to check out our site http://spr.ly/6589DgIyd. There you can put in all your information about your needs and plan and it will give you recommendations, dialing patterns, settings changes, and costs for various options. If you have any questions, just put them out here and we’ll gladly help out.
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