You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to travel from ORD to LAS. Can you help me to book a flight ticket?

ASSISTANT: Sure, can you provide me with the travel dates?

USER: I want to fly in the flight on Dec 25 and Dec 27.

ASSISTANT: Is there any connection limit?

USER: I am looking for a direct flight.

ASSISTANT: May I know if you have any time concern.

USER: I want to depart in evening time.

ASSISTANT: Is there any class specification?

USER: I prefer to travel in business class.

ASSISTANT: Do you have any airline preferences?

USER: No.

ASSISTANT: May I know the name please?

USER: Dorothy Thomas.

ASSISTANT: Give me a moment.

USER: Ok, take your time.

ASSISTANT: Dorothy Thomas, I regret to inform that there are no flights on your route with the given dates.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you very much for reaching us.