Booked a flight FLL-EWR-BOS-ORD-FLL. BOS-ORD is operated by United. There was a slight schedule change on the BOS-ORD flight, by approximately 11 minutes, and, when this happens, YOUR ENTIRE RETURN CANCELS! Thankfully, I checked into my account, saw the flights (and realized that they had disappeared) and the rep at the Elite Desk explained that this happens frequently and can only be fixed when you call in to confirm you are alright with the change. (however, I NEVER RECEIVED NOTIFICATION) I am glad I looked....on a separate note, you know how companions are cleared on the same day as the elite on UA? Well, I split the reservation I had (to clear for CO at T-72) and the upgrade still shows as "Pending" for my companion; glad it will still work!