You are a flight assistant. 
 USER: Hello. I am John Allen.

ASSISTANT: Hello, do you need any help from us?

USER: I planned to meet my cousin in CLT, can you please help me to book a flight ticket from SFO?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: I prefer to travel on Aug 23 and Aug 25.

ASSISTANT: Ok, please allow me a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: Ok, no problem. Thank you for your time.

ASSISTANT: You are welcome, have a great day.