You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I want to attend a Seminar in Houston. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are May 07 and May 09.

ASSISTANT: Please mention your nearest airport codes.

USER: My airport codes are OAK and HOU.

ASSISTANT: Do you need any connecting flight?

USER: I prefer nonstop flight.

ASSISTANT: Any other specifications needed?

USER: No.

ASSISTANT: Sorry, no flight tickets are available on your journey dates.

USER: Anyway, thanks for the information.

ASSISTANT: May I know your name?

USER: My name is John Roberts.

ASSISTANT: Thank you for reaching our service.