Joke: Airport

In an airport, passengers are waiting for their flight to arrive at gate 46. Then an announcement is made saying : " All passengers boarding flight SQ2990 from gate 46, please move to gate 21...Thank You" As told, the passengers took their bags and shifted to gate 21" After 5 minutes another announcement is made: " All passengers boarding flight SQ2990 from gate 21 please move back to gate 46...thank you" Now the irritated passengers dragged themselves back to gate 46. A minute later another announcement was made: "Thank you passengers of flight SQ2990 for taking part in the Airport exercise"