You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I oblige you today?

USER: Can you please help me to book flight ticket from DEN to LAS?

ASSISTANT: Sure, may I know your travel dates?

USER: My trip dates are Feb 26 and Feb 28.

ASSISTANT: Is there any connection limit?

USER: I prefer connecting flight.

ASSISTANT: Do you have any other requirements?

USER: I would like to depart in the evening.

ASSISTANT: May I know your name to proceed further?

USER: I am Frank Clark.

ASSISTANT: Sorry, there were no flights found on your route.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching us.