You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Christopher Wright.

ASSISTANT: How may I assist you?

USER: I am planning to visit Houston Zoo at HOU, could you please help me with booking a flight ticket from IAD?

ASSISTANT: Can you please mention your travel dates?

USER: I would like to take off on 09/13 and return on 09/15.

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 contacting us.

USER: Thank you for the information.