What was found
CREW STARTED DECENT FROM FL 450 TO FL 270, AT FL 350 THEY RECEIVED A CABIN DOOR SEAL CAS MESSAGE. CREW REFERRED TO EMERGENCY CHECKLIST E2 AND FOLLOWED TO PROCEED BELOW FL 310 WITH MASKED DON NORMAL. AT ABOUT FL 310 THEY RECEIVED A CABIN ALTITUDE CAS MESSAGE AND PROCEEDED TO DECLARE EMERGENCY AND REQUESTED TO DESCEND TO 15000 FEET. PROCEEDED TO DO THE EMERGENCY DESCENT MEMORY ITEMS AND THEN BACK IT UP WITH EMERGENCY CHECKLIST. A4 ON THE RED MESSAGE CHECK LIST. AS CREW LEVELED OFF THE CAS MESSAGE CLEARED AND PRESSURE WENT BACK TO NORMAL. PROCEEDED TO FLY SWF WHICH WAS THE INTENDED DESTINATION WITH NO FURTHER ISSUES ALONG THE FLIGHT. CORRECTIVE ACTION: REPOSITIONED CABIN ENTRY DOOR SEAL WARM AIR DUCT IAW CABIN DOOR SEAL PRESSURIZATION COMPONENTS WARM AIR DUCT ROUTING ATA 21-40. REMOVED AND REPLACED SECONDARY DOOR SEAL IAW 525B MM CH 52-10-00 OPS CHECKED GOOD. REPACKED O2 MASK IAW 525B MM 35-20-00