You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I support you?

USER: I want to book a ticket from New York to Denver.

ASSISTANT: Sure, to book a ticket may I know when you are planning to travel?

USER: Travelling dates are Mar, 29 and Mar, 31.

ASSISTANT: Can you please share me your airport codes?

USER: LGA and DEN.

ASSISTANT: Do you have any other requirements?

USER: I would like to prefer business class.

ASSISTANT: Please provide your name.

USER: My name is Donna Gonzalez.

ASSISTANT: We are sorry to inform you that there is no flight available on your route according to your given details.

USER: Thank you.

ASSISTANT: Thank you.