You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How can I assist you at this moment?

USER: Please book a ticket from New York, NY-JFK to Denver, CO-DEN.

ASSISTANT: Sure, can you please provide your travelling dates to proceed further?

USER: My travel dates are from 06/26 to 06/28.

ASSISTANT: May I know your good name please?

USER: My name is Frank Mitchell.

ASSISTANT: Frank Mitchell, there are no flight services available on your requested dates on this route.

USER: Thanks for your assistance.

ASSISTANT: Thank you for contacting us.