You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, do you need any help from us?

USER: Can you assist me to book flight ticket from DEN to JFK?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: My trip dates to travel on June 04 and return on June 06.

ASSISTANT: Ok, could I have your name please?

USER: Sure, I am Kevin Clark.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I prefer a connecting flight.

ASSISTANT: Ok, do you have any other specifications?

USER: No, thank you for asking.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: It's ok, thank you.

ASSISTANT: You are welcome, have a great day.