You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Ronald Roberts. I need to book a flight ticket from DFW to HOU, can you please help me for booking?

ASSISTANT: May I know your desired travel dates please?

USER: I would like to travel on 11/27 to 11/29.

ASSISTANT: There is no flight on your desired travel dates.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for choosing us.