In some cases, yes. A regulator with a single snapped cable or a minor jam can sometimes be repaired by replacing just that cable or freeing up the mechanism. Still, a regulator with stripped gears, a cracked carrier, or a bent frame usually can't be repaired reliably and must be replaced as a complete unit.
Whether a repair makes sense really comes down to what actually failed inside the regulator. A cable that's snapped near an accessible point can sometimes be re-routed or replaced on its own, especially on older, simpler cable-and-drum designs where the individual parts are more separable. This kind of targeted repair can save money compared to a full regulator replacement, but it only works if the rest of the mechanism, the drum, the tracks, and the plastic carrier are all still in good condition.
Most modern regulators, though, are built as a single sealed or riveted assembly rather than a collection of individually serviceable parts. Once gears inside the strip, a spring loses tension, or the frame that holds everything together bends or cracks, there typically isn't a practical way to repair just that one component without essentially rebuilding the whole unit, which usually costs more in labor than simply installing a new regulator assembly.
There's also a safety and reliability consideration. A window regulator holds several pounds of glass in place and controls its movement every time you use the window, so a patched-together repair on a part with hidden wear elsewhere can fail again soon after, sometimes with the window dropping into the door unexpectedly. Because of this, most shops recommend replacement over repair once the failure goes beyond a simple, accessible cable issue.
If your Jeep's window has stopped working, it's worth having someone open up the door and take a real look before assuming it needs a full replacement. Hoover Street Auto Repair in Ann Arbor can tell you honestly whether your regulator is a candidate for repair or needs to be replaced.