The Tiara and the HQ Sweet 16 (same machine) need a special tool to change the foot. Most consumers do not have that tool, that's why a dealer needs to do it. Also the foot needs to be set just right with the correct torque and the proper amount of bed clearance (both of which are set at the factory). I don't know about other long arm machines and how to change the feet, so I can't address that issue. I did buy the quick-change converter--about $70 on sale, but it includes the open toe foot and a replacement closed toe foot--and I will have my dealer install it if I decide I need it.