I actually had this happen in IAH a few weeks ago with a checked bag. I was flying IAH-DTW-BDL, and DTW-BDL was delayed before I even left IAH, so I switched to IAH-ATL-BDL via the DM line (the DL app was being wonky). For context, IAH-ATL departed about 90 mins after the IAH-DTW flight.

I asked the GA working IAH-ATL if there was any chance they could pull my bag from IAH-DTW, and she was like, "Maybe, but no guarantees." Fortunately, BDL is home, so not the end of the world.

Sure enough, I get a notification right after IAH-DTW pushed back from the gate that my bag had been retagged for my rebooked flights. I'm guessing that with the handheld scanners they use, it must've triggered an alert, and they had enough time to pull the bag and retag it. It probably also helped that I had a bit of lead time between the original flight and the new flight. Quite frankly, I was pretty surprised - I figured I wouldn't see it until the next day.