CORP ACFT FAILS TO ASSURE CANCELLATION OF IFR FLT PLAN WHEN CEO CHANGES DEST.

Narrative

AFTER WORKING S AROUND A LINE OF TSTMS (WHICH TOOK EXTRAORDINARY TIME); WE WERE CLRED WHEN ABLE DIRECT TO DALTON; GA. I COMMANDED THE LORAN TO DO THE SAME. THEN UPON ESTABLISHING VISUAL CONTACT WITH THE ARPT; I ADVISED WE HAD THE ARPT IN SIGHT FOR THE VISUAL; AND WE WERE CLRED FOR THE APCH; AND TOLD TO CANCEL IN AIR OR ON THE GND THROUGH THE RCO. DURING DOWNWIND TO BASE LEG THE CEO OF THE COMPANY ADVISED WE PROCEED ON TO CALHOUN; GA (6 MINS SE); OUR ULTIMATE DEST; BECAUSE OF THE STORM DELAY THAT WE WERE SHORT OF TIME. I ASKED OUR COPLT (NEW; RENTAL PLT; SECOND TIME IN COCKPIT) TO CANCEL IFR ON THE RCO FREQ ON HER #2 COM. SHE DID; BUT APPARENTLY EITHER FAILED TO SWITCH OVER TO HER #2 XMIT POS; OR HAD THE WRONG FREQ. THERE WAS APPARENTLY NO ACKNOWLEDGEMENT. WE WERE ALREADY AT CALHOUN BY THIS TIME; AND I CANCELLED ON THE GND THROUGH FSS TELLING THEM WE HAD ATTEMPTED IN THE AIR AND WERE NOT SURE WE WERE SUCCESSFUL. THEY ACKNOWLEDGED OUR CANCELLATION. THEN CHA APCH CALLS SAYING WE FAILED TO CANCEL; THEY HAD BLOCKED AIRSPACE AND HADN'T RECEIVED ANYTHING OVER THE RCO. MY FAILURE APPEARS TO HAVE BEEN IN NOT VERIFYING THE COPLT'S CORRECT USE OF THE #2 COM; WHETHER IT WAS THE COM SELECT SWITCH OR THE FREQ INCORRECTLY SET. PLUS SHE DID NOT INDICATE TO ME THAT SHE HAD NOT RECEIVED ACKNOWLEDGEMENT ON OUR CANCELLATION UNTIL I QUESTIONED HER ON THE GND. I SHOULD HAVE VERIFIED THIS IN THE AIR. I WAS BUSY FLYING THE PLANE WORKING AROUND THE BUILDUPS THAT WERE AROUND THE PLANE; AND LEFT THE WORK TO HER SINCE SHE IS A CFII/MEI WITH 1700+ HRS.