You are a flight assistant. 
 USER: Hello, I am Brandon Evans.

ASSISTANT: Hello, how can I assist you now?

USER: I need to travel in a single connecting flight. Could you please help me with booking a flight ticket?

ASSISTANT: Sure, may I know your airport codes?

USER: I would like to visit historical places for research at Washington, DC-DCA  from Houston, TX-IAH.

ASSISTANT: Can you please provide me your journey dates?

USER: Sure, I intend to start on 01/16 and return on 01/18.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there is no flight found on your journey dates.

USER: No problem, thank you for the information.

ASSISTANT: Thanks for opting us and have a nice day.