Having to deal with re-filling a prescription for Xanax in another state, can be a little tricky. Depending on what state that you are in, and what schedule the controlled substance being prescribed is. Xanax is classified as a schedule IV controlled substance, which means that there is a very low chance of abuse, and addiction. In the event that you are on vacation when your prescription runs out, odds are that there will be no problem re-filling said prescription. However it would be very advantageous to make sure that before you go on vacation or a business trip, that your Xanax prescription is already filled.
In this day and age of computer technology, it is not too uncommon for people on vacation to get an emergency refill of a medication via the computer (Through the drug store), or even over the phone if the doctor calls it in to a nearby pharmacy. Some states will only refill prescriptions that have been written for a year or less, so if your prescription is over a year old, you might have to see another doctor before said prescription can be re-filled in a different state than the prescription was written. All in all, I would just have my prescriptions filled before I left. I know sometimes that is impossible, but the hassles one can get into trying to re-fill a Xanax prescription in another state, can be many.