You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am David Lewis.

ASSISTANT: How can I assist you today?

USER: I have to attend a Live Concert at Las Vegas, could you please help me with booking a flight ticket from EWR to LAS?

ASSISTANT: Sure, can you please share your travel dates?

USER: I would like to depart on Mar 6th and return on Mar 8th.

ASSISTANT: Do you have any class preference?

USER: I prefer business class.

ASSISTANT: May I know your connection limit?

USER: I am looking for a direct flight.

ASSISTANT: Is there any requirement that you are looking for?

USER: Make sure that my depart time is afternoon.

ASSISTANT: David Lewis, I am sorry to inform you that there is no flight available at your request.

USER: Ok, not an issue. Anyways, thank you for the information.

ASSISTANT: You are welcome. Thank you for contacting us.