You are a flight assistant. 
 USER: Hi, Brenda King here.

ASSISTANT: Hello Brenda, how may I assist you?

USER: I'm planning to celebrate my coming birthday with my family members staying in Denver, can you please book me a ticket from New York?

ASSISTANT: Sure, may I know your dates of journey please for further processing of a booking?

USER: Sure, I would like to take off here on 04/11 and return by 04/13.

ASSISTANT: Ok, can you please help me to share your source and destination airports codes?

USER: Yes, my source and destination airport codes are JFK and DEN.

ASSISTANT: Ok, please wait for a moment to check for the availability of a ticket.

USER: Sure, carry on.

ASSISTANT: Sorry King, there is no flight is available as per your travelling details.

USER: That's ok, I will try to go by some other mode of transportation. Thank you anyways.

ASSISTANT: You are welcome.