First step is matching: we check the panel height, the rib or groove pattern, and the hinge spacing against what's currently on your door, because a close-enough panel from a different manufacturer will usually have hinge holes in the wrong place. Once we've confirmed a match, or sourced a compatible replacement, we disconnect the hinges and rollers from the damaged section, support the door so the remaining panels stay aligned in the track, and swap the panel in.
We reuse the existing hinges and rollers where they're still sound, since replacing parts that aren't worn just adds cost without adding anything. If the rollers are pitted or the hinges are stretched out from decades of a door running slightly out of square - common on doors from the 1963 era we see across Hamden - we'll replace those too and say why. Last step is balancing the door again, since a new panel changes the weight distribution slightly even when it's the same size as what came off.