You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Stephen Robinson here.

ASSISTANT: Stephen, how can I assist you?

USER: Please book my ticket from DFW to HOU.

ASSISTANT: Sure, can you please let me know your travel dates?

USER: My trip dates are 08/12 and 08/14.

ASSISTANT: Ok, please wait for while.

USER: Sure.

ASSISTANT: Sorry Robinson, there are no flights available on your given travel dates.

USER: No problem, thank you.

ASSISTANT: You are welcome and thank you for choosing us.