Most modern vehicles have electronic parking brakes. If you’re doing the rear brakes you usually need a scan tool to place the brakes into a “service mode” or to retract the calipers. Kind of annoying, but honestly any shop with a decent scan tool should be able to do it. Some vehicles (Mazda for one) have a manual procedure you can do that requires no scan tool at all. It definitely doesn’t have to go to a dealer, but at least another shop with the proper equipment.