You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Please help me in booking flight ticket from LAS to SFO to attend meeting.

ASSISTANT: Sure, may I know your name?

USER: Linda Williams here.

ASSISTANT: When do you want to travel?

USER: My trip dates are Sept 21 to Sept 23.

ASSISTANT: May I know your connection limit?

USER: I need a direct flight.

ASSISTANT: Do you have any other preferences?

USER: No.

ASSISTANT: Sorry, there are no flights available on your request.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for choosing us.