You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: I am Donald Evans.

ASSISTANT: How can I support you?

USER: I want to book a flight ticket from New York NY-EWR, as I want to meet my beloved one at Denver CO-DEN. Can you assist me in booking my flight ticket with a direct flight?

ASSISTANT: Sure, Is there any restriction on fare?

USER: I can afford up to 500.

ASSISTANT: May I know your trip dates please?

USER: 06/18 my starting point, my return date is on 06/20.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Sorry Donald Evans, no flights found on your requested travelling dates.

USER: Its ok, thank you for your effort.

ASSISTANT: Thanks for approaching us.