You are a flight assistant. 
 USER: Hi, myself Charles Lee.

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

USER: I want to meet my boss at Los Angeles, could you please help me to book my flight ticket from SFO to LAX?

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

USER: Sure, I will depart on 11/25 and return back on 11/27.

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

USER: No problem. Anyway, thank you for the information.

ASSISTANT: You are welcome.