You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I would like to visit Las Vegas, can you please help me to book my flight ticket from IAD to LAS?

ASSISTANT: Ok, please can I know your name to book a ticket as per your concern?

USER: Thank you. My name is Anna Robinson.

ASSISTANT: Can you let me know the dates of your journey?

USER: I want to depart on Aug 20th and return back on Aug 22nd.

ASSISTANT: Sure, please let me know your specifications.

USER: I need a flight having single connection.

ASSISTANT: Sorry, there are no flights available at your provided locations to book.

USER: Sad to hear that. Anyway, thank you for checking.

ASSISTANT: Thank you for choosing our agency.