You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Anna Hall.

ASSISTANT: How may I aid you today?

USER: I am planning to attend business meeting at DCA, Washington. Can you please help me with booking a flight ticket from IAD?

ASSISTANT: Sure, I will help you in booking flight ticket. Can you please let me know your travel dates for booking flight ticket?

USER: Sure, I would like to take off on 07/07 and return back on 07/09.

ASSISTANT: Ok, just give me a moment, I will check flight availability.

USER: Ok, but please make sure that the price limit does not exceed 500.

ASSISTANT: Sure. Sorry for the inconvenience, no flights available as per your requested dates.

USER: Ok, no issues. I will try another way to complete my trip. Thank you for checking.

ASSISTANT: Thank you for choosing us, have a good day Anna Hall.

USER: You are welcome.