You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am planning to visit tourist places in LAS, can you please book a flight ticket from SFO?

ASSISTANT: Sure, please provide your itinerary dates.

USER: My trip dates are 04/16 and 04/18.

ASSISTANT: Please hold on for a while.

USER: Ok.

ASSISTANT: May I know your name?

USER: Melissa Brown is my name.

ASSISTANT: Sorry Brown, there is no flight availability.

USER: Ok, fine. Thank you for checking.

ASSISTANT: Thank you for choosing us.