It ultimately depends on a number of factors:
1- Domestic or International?
2- Did an agent proactively (or did you request they) submit a Baggage Deviation?
3- How much time before departure did this happen?
Generally if no BDR is submitted for a domestic flight it will ride as checked, go out to baggage claim and then get swept off the belt by the Baggage Service Office team if not claimed in a "reasonable" period of time (with "reasonable" depending a lot on the airport and how busy things are... In Richmond I've seen bags on the belt hours after arrival; in Cleveland the BSO usually collects everything within a half hour at the latest.
If a BDR is submitted for a domestic flight and there's enough time before departure it may get pulled and returned to you (if you requested) otherwise it could be held at the originating station then forwarded on the rebooked flight or (less frequently) forwarded on the original flight and held at the destination. This cutoff may vary depending on if it's a aircraft supporting containerized (LD3) baggage vs. bulk baggage. A "Status Pending" tag applied by the counter at check-in may increase the odds of a successful pull as those tend not to be loaded until the last minute.
If its international and the change is voluntary PPBM will force the bag to be pulled before departure. Involuntary changes will still frequently result in a pull at origin.
Originally Posted by
nomad420
They will ship your bags home if the original flight is greater than one hour later arrival than the one you are on otherwise you'll be asked to wait for the bags. The one hour deal is at least the case at SFO, other UA baggage office may have different rules.
I think there's a general "request" but I think if you wanted to stand your ground assuming that the reason for the delay isn't "your fault" (late checked bag, etc.) they will deliver. I had an exhausting trip in ~2021 where I (on a rebooked connecting flight, due to maintenance) arrived 5.5 hours late but my bag was on the original (nonstop) flight that was due in ~50 minutes after I got there -- so of course that doesn't mean bags will be on the belt in 50 minutes -- They asked me to wait; I told the BSO, politely of course, that United already wasted more than 5 hours of my life, I had little interest in waiting another hour+ at the airport and they had no problem setting up the delivery.