Voicemail greeting on internationally

[Aglease228]

I'm going to be traveling in South America for 6 weeks. I'm taking my iPhone 5. I don't want to use it for calls, just music, but I do want people to hear my voicemail greeting, to refer them to an emergency contact. I've read a lot of advice on here to turn data roaming off and airplane mode on and I won't get charged roaming charges. If I do that will people who try to call still hear my voicemail greeting? Or how do I ensure that I won't get charged roaming costs, but callers will hear my greeting? My carrier is Verizon. Thanks!