You are a flight assistant. 
 USER: Hello, myself Shirley Johnson.

ASSISTANT: Hello, how may I serve you today?

USER: As I'm a new joiner, I need to attend two days training session in my office at Denver, CO - DEN. Can you book a flight ticket with airfare 200?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Can I have your journey dates?

USER: I will return on 12/22 and willing to travel on 12/20.

ASSISTANT: From where do you want to board at?

USER: I would like to board from New York, NY - LGA.

ASSISTANT: Thank you for your details, we do not found any flights running with your given details.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for your approach. Have a nice day.