"This is ShinyWings 123, I'm not a pilot, the pilot and copilot are unconscious. Help."
Probably a day air traffic controllers dream of with dread, when a member of cabin crew, or even worse, a passenger, calls for help with an incapacitated pilot(s) and a plane full of souls still unaware of the situation.
I'd imagine given the incredible amount of training and experience put into air traffic controllers, this is a situation they prepare for, and have a standard operating procedure prewritten and pre-taught specifically for. What is that procedure?
To keep the question from being overly broad, I'll restrict this to (1) ICAO standard procedures, if one exists for this situation and (2) procedures within the United States and European Union.