You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I need to book a flight ticket from LAS to SFO, Can you please help me for booking?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: I would like to travel on 03/05 to return on 03/07.

ASSISTANT: Do you have any specifications?

USER: I need a direct flight.

ASSISTANT: May I know your good name please?

USER: Shirley Allen.

ASSISTANT: Sorry, there is no flight available on your requested dates.

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

ASSISTANT: You are welcome.