My family has a vacation planned Feb. (Phoenix AZ if that makes any difference). I always think it would be fun to go for a short flight when on vacation. Will flight schools give a "discovery flight" to someone that is already a pilot, and lives out of the area and has no plans of actually doing any further flight training?
I don't know about a "Discovery Flight." The lessons that go by that name tend to be discounted, very short, and are intended as a marketing tool for new students.
OTOH, if you are talking about a local lesson, all it takes is a call or email to a local flight school. I used to do that all the time. In some cases, it was a checkout to bee able to rent the airplane, but others it was a single flight.
Just of the top of my head without checking my logbook, I'm recalling flights in Hawaii, to Catalina Island in California, a glider lesson in Minden while on vacation in Tahoe, flight and landing below sea level over the Salton Sea with a landing at KTRM in a Tiger (my first flight in one) at Thermal, a great day of instrument flying out of Hilton Head, a flight around the Seattle area ...** Those were single flights. Then there were checkouts for later use in Florida, Napa County, .... I may have some kind of record doing this.
When I was based in Colorado, I used to do those kinds of flights with visitors all the time who wanted a taste of density altitude or a landing at a mountain airport.
** Oh! And how could I forget
this one before we got on the cruise ship, or the one up a glacier out of Anchorage, after the cruise was over.