You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Edward Lewis.

ASSISTANT: How may I assist you?

USER: I have planned to visit Olympic National Park at Washington, could you please help  me with booking a flight ticket from IAH?

ASSISTANT: May I know your destination airport code?

USER: My nearest destination airport code is DCA.

ASSISTANT: Can you provide your travel dates?

USER: I would like to take off on 05/15 and return on 05/17.

ASSISTANT: Sorry, there is no flight found basis on your details.

USER: That's ok, I will find an another alternate way to complete my trip.

ASSISTANT: Thank you for reaching us.

USER: You are welcome. Thank you for the information.