You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Myself Anthony Hall. I am planning my week day to visit Las Vegas. Can you please help me in reserving the ticket from IAD to LAS?

ASSISTANT: Sure, can you please share your travel dates?

USER: I am planning my trip on Apr 16, and again I will return back on Apr 18.

ASSISTANT: Do you have any class preference?

USER: I am comfort with any class.

ASSISTANT: Is there any other specification that you are looking for?

USER: My depart time is evening.

ASSISTANT: Anthony Hall, I am sorry to inform you that there is no flight available during evening time.

USER: Not a big problem, anyhow I will choose an other way to reach my destination.

ASSISTANT: Thank you for contacting us.

USER: Thank you very much for your kind information.

ASSISTANT: You are welcome.