If it’s the 6F35 which the 2.5s use, there is a drain plug on the bottom of the case, and the filter is non-serviceable. IF you have a dipstick, you can easily do the service yourself. Jack it up, pull the drain plug, measure the fluid removed, and replace it. Then verify on dipstick. Then, disconnect both battery terminals (or use the trans logic reset mode on ForScan if you have it) for 15-20 mins to reset the PCM. It’s the shift logic you want to relearn. New fluid only partially improved my shifting, but the fluid plus the PCM made a 90k mile trans shift like brand new.
If you don’t have a dipstick it’s harder because there’s a tiny little stub and it’s a PITA for the average person. Maybe try taking it to a Ford dealer since they essentially use the same stuff?