You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I planned to meet my friend in DCA, can you please help me to book a flight ticket from DEN?

ASSISTANT: Sure, I can help you. May I know your travel dates?

USER: I prefer to travel on Jul 25 and Jul 27.

ASSISTANT: Ok, is there any class preference?

USER: No.

ASSISTANT: Ok, please wait for a while.

USER: I would like to return back in evening. I prefer to travel in a connecting flight.

ASSISTANT: As per your requirements, there is no flight available on your given travel dates.

USER: Ok, no problem.

ASSISTANT: May I know your name?

USER: I am Linda Lewis.

ASSISTANT: Thank you.

USER: Thank you for your information.