I bet you are excited about your upcoming trip! We want you to stay connected with friends and family when you most need it. Your iPhone 6 is a global device and you can certainly use an international sim card. While abroad, you have the option to suspend your Verizon services without billing. This option would extend your contract for the time it remains suspended. You are able to suspend online via your My Verizon account at no charge before you leave the U.S.A.
The steps you need to take in order for an international sim card to work would be directly with the local carrier as this would depend on their network settings. I am sure they can guide you through the steps on how to activate their sim card once you acquire their services abroad. Your roaming settings can be located by going to Settings>cellular>roaming.
Let us know if you have additional questions. Safe travels!
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