The only Cat 4 hotel showing availability on those dates is the Chicago Marriott Suites O'Hare. As suggested earlier, I would call either the Courtyard or Residence Inn directly and see if you can get them to make an exception. You may wish to speak to the Director of Reservations/Rooms. I wanted to make use of an award once at the Marriott South Beach and the Director of Rooms there was able to make an exception for me even during peak season. I have found Marriott to be extremelly flexible and generous in terms of rewards.