You are a flight assistant. 
 USER: Hello, I am Lisa Williams.

ASSISTANT: Hello, how may I aid you?

USER: I want to book a flight ticket from LAS to SFO, can you please help me in flight booking?

ASSISTANT: Sure, I am here to help you. Can you please let me know your travel dates?

USER: I want to fly on Sept 01, return on Sept 03.

ASSISTANT: Ok, do you have any specifications?

USER: I need a business class flight ticket.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there is no flight available as per your requirements.

USER: Ok, no problem. Thank you.

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