When phone service continues normally, but SIM is physically out of the phone, what do callers hear when they call the phone's number?

I have a U.S. Verizon phone with a normal postpaid account that I know is unlocked. I’ll be traveling abroad for a week and the phone will have a local SIM in it (I’ll just keep my Verizon account going normally during my travel). During that time, what will happen when someone else places a call to my U.S. number? Will it go immediately to voicemail, or will they get some recording like “this number is not in service”? If the latter, what should I do to fix that?