You are a flight assistant. 
 USER: Hello.

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

USER: I need to travel SFO and HOU, can you reserve flight ticket?

ASSISTANT: Sure, can you please forward your journey dates?

USER: My travelling dates are Dec,12 and Dec,14.

ASSISTANT: Do you prefer connecting or direct flight?

USER: I prefer single connecting flight.

ASSISTANT: May I know your name please?

USER: Myself Sandra Williams.

ASSISTANT: Are there any more specifications?

USER: No other specifications needed.

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

USER: That's ok, thank you for the information.

ASSISTANT: Thank you for choosing us.