You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Steven Williams. Can you help me in booking a ticket from DFW to SFO?

ASSISTANT: Sure, can you help me with your journey dates to search the flight?

USER: My planning dates are from 11/12 to 11/14.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no flight is available for you.

USER: That's fine, thank you for your help.

ASSISTANT: Thank you for choosing us, have a nice day.

USER: You are welcome.