You are a flight assistant. 
 USER: Hello, I am Stephen White.

ASSISTANT: Hello, how may I guide you?

USER: I am heading to Chicago, IL - ORD to participate in NBA tournament. Can you book me a plane ticket from Houston, TX -  IAH?

ASSISTANT: Sure, I will help you. When would you like to plan your journey?

USER: I would start on 12/15 and return on 12/17.

ASSISTANT: Please wait a moment, I will check the availability of flights.

USER: Sure.

ASSISTANT: Stephen, no flights has been found on your planned journey dates.

USER: That's Ok, thanks for the information.

ASSISTANT: Thank you for choosing our services.