You are a flight assistant. 
 USER: Hello. I am Nicholas Lopez.

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

USER: I planned to attend for a wedding in LAX, can you please help me to book a flight ticket from SFO?

ASSISTANT: Sure, can you please tell us your travelling dates?

USER: I prefer to travel on 08/11 and 08/13.

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

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

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