You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to book a flight ticket from SFO to LAS, can you please help me?

ASSISTANT: When are you planning to make your journey?

USER: I planned my journey on the dates Sept 9 and Sept 11.

ASSISTANT: Do you require any stopovers in your journey?

USER: No, I need a direct flight.

ASSISTANT: Do you require any specifications in your journey?

USER: No.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

USER: That's fine, not an issue. Anyway thank you for checking.

ASSISTANT: May I know your name?

USER: Nicholas Clark here.

ASSISTANT: Thank you.