2 ACR MLGS HAD A POTENTIAL AIRBORNE CONFLICT THAT WAS RESOLVED BOTH BY TCASII AND APCH CTL.

Narrative

FO WAS FLYING. THIS WAS THE 4TH LEG OF 6 SCHEDULED AND FLOWN. WINDS WERE SHIFTING AT THE DENVER ARPT. WHEN WE CROSSED THE KIOWA VOR; DEN WAS DEPARTING RWY 8 AND ARRIVING RWY 35L/R. CAPT WAS GETTING ATIS AND TALKING TO COMPANY OPS. DEN APCH DSNDED US FROM 12000 FT TO 10000 FT. I ANSWERED ON THE RADIO AND COMPLIED ON THE AUTOPLT; ANTICIPATING AN APCH TO RWY 35L/R. I WAS WATCHING THE TCASII AS THE CAPT GOT BACK IN THE LOOP AND WAS POINTING OUT A POTENTIAL CONFLICT WHEN; BEFORE THE CAPT COULD CALL THEM; DEN APCH (SUPVR I ASSUME) GAVE US AN IMMEDIATE CLB TO 11000 FT. I DISCONNECTED THE AUTOPLT AND CLBED WITH FULL PWR TO 11000 FT. AS WE LEFT 10000 FT; THE TCASII CLB COMMAND ACTIVATED. ATC RPTED THE DEPARTING ACFT (ALSO AN MLG SAW US VISUALLY). WE SAW THEM AT LESS THAN A MI. CLOSEST APCH WAS 1300 FT VERT; 200 HORIZ. OVERALL; I FEEL EVERYONE DID THEIR JOB. CONTRIBUTING FACTORS: I WAS TIRED. PREVIOUS TRIP WAS A 7 HR LATE NIGHT FOLLOWED BY 3 CONSECUTIVE XA00 WAKE-UPS. I GOT 4 HRS OF SLEEP THE NIGHT BEFORE AND INFORMED THE CAPT. IT WAS A LONG; HOT DAY. PROCS WERE COMPRESSED ON A SHORT LEG. RWYS WERE CHANGING AT DEN FROM 35L/R TO 17L/R. THIS CAUSED SOME CONFUSION; I BELIEVE. I MIGHT HAVE QUESTIONED THE DSCNT TO 10000 FT BUT I EXPECTED AN ARR ON RWY 35L. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTING FO BELIEVES THAT IT WAS AN ATC FAULT; ALTHOUGH BOTH HE AND HIS CAPT WERE VERY TIRED. THE CREW CALLED TRACON WHO SAID THAT THERE WAS NO CONFLICT. THE CREW HAS HEARD NO MORE ABOUT THIS FROM THE FAA.