You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to book a flight ticket to Washington DC-IAD, help me in booking my flight ticket from Denver CO-DEN.

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

USER: I want to start on 12/12, my return date is on 12/14.

ASSISTANT: Do you need a halt in between your journey?

USER: I need a connecting flight.

ASSISTANT: May I know your good name?

USER: I am Rachel Smith.

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

USER: That's ok, thank you for your effort, I will find out other alternative.

ASSISTANT: Thank you for reaching us.