B737 DSNDING INTO DEN WITH ZDV RESPONDED TO CLRNC FOR ANOTHER ACFT.

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WE WERE ASSIGNED TO DSND FROM FL350 TO FL270. AT ABOUT FL280; FO TURNED ON THE SEATBELT SIGN AND BEGAN HIS APPROPRIATE PA. AT ABOUT FL275; I HEARD ZDV CLR US TO CROSS QUAIL AT 17000 FT AND READ IT BACK. WHEN DONE XMITTING; I HEARD ANOTHER ACFT ALSO READING IT BACK. THEN DENVER SAID THE CLRNC WAS FOR ACR Y. I HAD ALREADY ENTERED 17000 FT IN ALT WINDOW AND WAS THROUGH FL270 DURING THE CORRECTION. WE LEVELED AT FL266 AND DENVER THEN CLRED US TO QUAIL AT 17000 FT. WE HAD STARTED SLOW CLB BACK TO FL270; GOT AS HIGH AS FL277; THEN STARTED THE DSCNT AGAIN. NO TFC CONFLICTS WERE NOTED ON OUR TCASII DURING THIS TIME. FACTORS: ONE PERSON HEARING THE CLRNC -- I WAS SURE I HEARD OUR CALL SIGN; BUT NOTICED THAT WE HAD BEEN FLYING WITH ACR Y'S CALL SIGN EARLIER. IT'S POSSIBLE I REACTED TO IT IN ERROR. SUPPLEMENTAL INFO FROM ACN 606827: THE COMBINATION OF EXPECTING THE DSCNT CLRNC; HEARING IT GIVEN TO A FAMILIAR FLT NUMBER; AND ONE PERSON OFF THE FREQ AT PRECISELY THE WRONG TIME; LED TO THIS ALTDEV. ALTHOUGH THE CTLR MAY HAVE ALLEVIATED THE DEV WITH A TIMELY CLRNC; IT STILL OCCURRED. SOMETIMES THERE IS A NEED FOR AN IMMEDIATE RESET OF THE ALERTER TO MAINTAIN A TIGHT DSCNT PROFILE. HOWEVER; IF THERE'S NO RUSH; A CONFIRMATION PER SOP'S CERTAINLY IS APPROPRIATE. ALTHOUGH THERE WAS NO TECHNICAL VIOLATION OF SOP; THE CAPT COULD HAVE WAITED A FEW SECONDS FOR THE ALT CAPTURE AND ALLOWED ME TO CONFIRM THE LOWER ALT WHEN I CAME BACK ON FREQ.