You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Can you aid me to book a flight ticket from IAD to DEN?

ASSISTANT: Sure, I am here to help you. Can I have your journey dates?

USER: My trip dates are Jul 23 and Jul 25 respectively.

ASSISTANT: Do you need any connection limit?

USER: I prefer for connecting flight.

ASSISTANT: Do you need any other specifications?

USER: No specifications.

ASSISTANT: May I know your name?

USER: Kevin Lopez here.

ASSISTANT: There are no flights available on your routes.

USER: Thank you.

ASSISTANT: Thank you for choosing us.