You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I am Brian Walker from New York. I am planning to attend a Snooker's competition in Denver. Can you make a reservation for me?

ASSISTANT: Sure, I am glad to help you with that.

USER: Thank you.

ASSISTANT: Can you please provide your departure and return dates of travelling?

USER: Sure, I want to airborne on 12/09 and recur on 12/11.

ASSISTANT: Ok, may I know your origin and destination airport codes for booking?

USER: Ok, my airport codes are from LGA to DEN.

ASSISTANT: Please wait for a minute.

USER: Ok, take your time.

ASSISTANT: Sorry to inform you that, there are no flight's available based on your travelling dates.

USER: Oh! Sad to hear that. Anyway, I will find another alternative to complete my journey. Thank you for the information.

ASSISTANT: Thank you for contacting us. Have a nice day.