When somebody is leaving the room you are in, call his name loudly, show them that you need their attention, pretend you have some kind of problem, best if they come to back to you. "What do you want?" "Have nice day" "Safe journey home" "See you next week" Works almost everytime.

Robert van der Veeke Basugasubasubasu Basugasubakuhaku Gasubakuhakuhaku!! "Better is the enemy of good enough." Dr. Mikoyan of the Mikoyan Gurevich Design Bureau.