You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Can you help me to book a flight ticket from DCA to DEN?

ASSISTANT: Sure, I am happy to help you. Can you please let me know your travelling dates?

USER: My trip dates are Apr, 25 and Apr, 27.

ASSISTANT: Do you prefer any break in between journey?

USER: I need direct flight.

ASSISTANT: Are there any other specifications for you?

USER: No.

ASSISTANT: May I know your good name?

USER: Robert Perez here.

ASSISTANT: Sorry, no flights are available on your journey routes.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you for availing us.