You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I serve you at this moment?

USER: Can you help me to book flight ticket from HOU to OAK?

ASSISTANT: Sure, may I know when are you planning to depart and return?

USER: My trip dates are Aug 16 and Aug 18.

ASSISTANT: Do you prefer either economy or business class?

USER: I am comfortable with any class.

ASSISTANT: Is there any specific airline are you looking for?

USER: I prefer normal cost airline.

ASSISTANT: Do you have any connection limit?

USER: No.

ASSISTANT: We don't have any flight available which meets all your requirement.

USER: Ok, not a problem.

ASSISTANT: May I know your name for our record purpose?

USER: Myself Richard Roberts.

ASSISTANT: Thank you.

USER: Thank you.