You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Linda Evans, want to travel from OAK to LAS for my business trip. Can you please help me?

ASSISTANT: Sure, may I know your trip dates please?

USER: My trip dates are from 12/13 to 12/15.

ASSISTANT: Please wait for a while.

USER: Ok, take your time.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: That's fine, thank you.

ASSISTANT: Most welcome.