What carrier? Are you using the same phone # or is it a local # where you are traveling to ? Where are you traveling to ? Did you have to add any new features or plans ? Should not be any issues using the phone internationally.
Not enough information to answer your question.
Going overseas soon and have received a SIM card from my cell carrier that will all me to use my iPhone 6x Pro. Not sure WHEN to swap SIM cards. Can I swap a day before I leave or do I have to wait until I land on foreign soil? Any help here is appreciated.