You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you?

USER: I am Margaret Allen here, I would like to reserve my ticket from IAD on 11/27?

ASSISTANT: Sure, may I know your destination airport code and return date to travel?

USER: Sure, my destination airport code is LAX and my return date is on 11/29.

ASSISTANT: Please wait for a while.

USER: Sure, take your time.

ASSISTANT: Sorry for the inconvenience, there is no flight available on your requested dates.

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your service.