You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, please tell me for what help you approached us?

USER: I am Elizabeth White. I am planning to travel from IAD to LGA, can you help in finding a flight?

ASSISTANT: Sure, may I know your trip dates?

USER: I like to travel on 08/28 to 08/30.

ASSISTANT: Sorry, there is no plane with your requested travel dates.

USER: That's ok. Thank you for your information.

ASSISTANT: Thank you for choosing us, have a great day.