Originally Posted by rickair7777

Neither the company nor the union can do that unilaterally. Even if they agree to do it, it would almost certainly get tossed by the courts as age discrimination. Not going to happen.

Even a CBA can't take away someone's seniority just because they reached a certain age. If they're legal to be employed, and already on the list, they're going to keep their seniority. How much schedule accommodation they get is another story.