A FLT CREW RE-FILED A FLT PLAN WITH CLRNC DELIVERY. BOTH THE PILOTS AND ATC MISUNDERSTOOD WHAT EACH THOUGHT THE CLRNC WAS SO THE FLT CREW DEVIATED FROM THE ATC ROUTING IN FLT.

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FLT RELEASE FLT PLAN: STL; VOR1; VOR2; DEST. CLRNC DELIVERY ISSUED; STL; CARDS7; NEENS TRANSITION; VOR1; VOR2; DEST. CAPT AND FO CONSULTED RADAR (WX) AND DECIDED IT WOULD BE BETTER FOR WX AVOIDANCE TO CHANGE OUR DEP TRANSITION FROM NEENS TO SPI; KEEPING THE REMAINDER OF THE FLT PLAN THE SAME. FO SPOKE WITH DISPATCH ABOUT THE RTE AMENDMENT AND THE RELEASE WAS AMENDED TO REFLECT THE RTE: STL; CARDS7; SPI TRANSITION; VOR1; VOR2; DEST AND NEW FUEL NUMBERS. FO CALLED CLRNC DELIVERY BACK TO ASK IF THE NEW FLT PLAN HAD BEEN RECEIVED. CLRNC DELIVERY SAID NO AND FO ASKED CLRNC DELIVERY TO CALL US BACK WHEN THE NEW FLT PLAN CAME THROUGH THE SYS. MINS LATER; CLRNC DELIVERY CALLED BACK; AND STATED HE DID NOT HAVE THE NEW FLT PLAN SO HE TYPED ONE IN ON HIS OWN. THE NEW CLRNC WAS 'CLRED TO DEST VIA CARDS7; SPI; DIRECT.' FO READ BACK; 'CLRED TO DEST VIA CARDS7; SPI; DIRECT AS FILED.' THIS IS WHERE WE UNDERSTOOD THE ONLY CHANGE TO OUR RTE WAS THE DEP TRANSITION FROM NEENS TO SPI (THEN TO VOR1; VOR2; DEST AS ORIGINALLY CLRED). THE RTE WE FLEW WAS THE ONE ON OUR AMENDED RELEASE; IN THE FMS; AND THAT WE UNDERSTOOD WE WERE CLRED TO DO BY CLRNC DELIVERY. WHAT WE DIDN'T KNOW WAS THAT CLRNC DELIVERY HAD TOTALLY CHANGED OUR ENTIRE RTE TO STL; CARDS7; SPI; DEST. ATC CTR CONTACTED THE CAPT TO INQUIRE ABOUT A POSSIBLE DEV. AFTER CTR REVIEWED THE CLRNC DELIVERY TAPE; CTR DECIDED THERE WAS TOO MUCH AMBIGUITY IN THE CLRNC TO FAULT EITHER PARTY. CLRNC DELIVERY FELT THEY HAD COMMUNICATED THE NEW RTE AND WE THOUGHT WE UNDERSTOOD THE NEW RTE; HOWEVER; WHAT WE BOTH UNDERSTOOD TO BE CORRECT DID NOT AGREE. THE BREAKDOWN IN COM HAPPENED BY CLRNC DELIVERY SAYING 'DIRECT' (WHICH WE THOUGHT WAS DIRECT VOR1 WHEN IN FACT HE MEANT DIRECT DEST). CTR STATED TO CAPT THAT UPON REVIEW; NO PLTDEV HAD OCCURRED.