I booked a business class ticket last september for BRU-ORD-SFO (UA973) departing 03/23. Just checked this morning and my booking was listed as Z-coach with no seat assignment. Fortunately my original seats 7A/2A were still available. I phoned United and it took about one hour to fix this glitch. I wonder what would have happened if I would not have checked my reservation in advance?