I ran into this exact question when planning a quick work trip to Fresno. Sadly, Southwest doesn’t serve FAT airport. I only found out after calling their support team ☎️ because I was trying to switch an existing reservation to Fresno using my travel funds. The rep confirmed it wasn’t possible and showed me how to cancel my ticket properly to avoid losing value. If you ever need to verify routes or change bookings instantly, calling them directly is honestly the best move—quicker than browsing the site.