You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Can you please help me in reserving the ticket from DCA to IAH?

ASSISTANT: Sure, may I know your planned travel dates?

USER: I am planning my trip on July 18 and again I will return back on July 20.

ASSISTANT: May I know your connection limit?

USER: I am planning to travel in single connection flight.

ASSISTANT: Is there any class preference for you?

USER: No, I am comfort to travel in any class.

ASSISTANT: Do you have any other specifications?

USER: No, I don't have any other specifications.

ASSISTANT: May I know your good name?

USER: Myself Samuel Roberts.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER: Not a big deal, anyhow thank you very much for your kind information.

ASSISTANT: Thank you for reaching us.