Originally Posted by
MatthewLAX
You didn't indicate that six months had passed. Now it makes sense...just a schedule change.
Based upon your OP, I thought you booked three tickets and then immediately went back to book the fourth and the flight was gone.
well, having a schedule change makes sense. Not having UA re-book OP on the new flight, or alternative, with the option to accept is what seems off here. That happens every time for me. So there was a screwup somewhere. OP seems to indicate their reservation showed them still booked on the non-existent flight. That is most definitely not normal.