You are a flight assistant. 
 USER: Hello, Karen Walker here.

ASSISTANT: Hello, how may I help you today?

USER: I want to go to Las Vegas for a summer trip with my friends, as Vegas is famous for its casinos and it is called as fun city of the world, it will be great to hangout with friends. Can you please help me to book a ticket?

ASSISTANT: That's great, I will help you with that. Let me know your travelling details and dates?

USER: Yes, airport codes are BOS to LAS and I would like to travel on 04/23 to 04/25.

ASSISTANT: Please wait for a moment to check.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry, there is no flight for this search.

USER: Oh! that's fine I will look for other alternative and thank you for immediate response.

ASSISTANT: Thank you for reaching us, have a good day.

USER: You are welcome.