You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: Can you please reserve me a flight ticket from PHL to LAS?

ASSISTANT: Sure, I can help you to reserve the flight ticket. Can I know your departure and arrival dates please?

USER: My travel dates are from Dec 23rd to Dec 25th.

ASSISTANT: Ok, please share your preference about the airlines.

USER: I prefer a business class to travel.

ASSISTANT: Ok, please tell me your respective name to proceed further.

USER: I am Timothy Clark.

ASSISTANT: Sorry to inform you that, there are no flights available in the business class on the dates you have given.

USER: Ok, no problem. Thank you.