Military
Air Traffic Control Fully Certified
Other / Unknown
Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action; General Declared Emergency
Aircraft
Aircraft X was in a descent to FL220 and turned 10 degrees right for departure traffic coming out the departure gate. I advised aircraft X that there would be a delay at FL220 for enroute traffic. While in the descent; aircraft X declared an emergency and requested lower. I advised aircraft X that I could not give a clearance for lower because of a King Air. Position of the King Air was approximately 2 to 3 miles southeast of aircraft X. I asked aircraft X to verify he had declared an emergency because the radios where not very clear. He affirmed; I then called traffic to aircraft X (the King Air) and advise when leaving FL200; aircraft X relayed that they were already out of FL190.
Enroute Controller described a loss of separation event when a military aircraft with an emergency descended prior to receiving ATC clearance.