You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I would like to visit Las Vegas for my conference meeting, could you please help me to book my flight ticket?

ASSISTANT: Sure, I am here to help you in booking. Can you please share your travel dates?

USER: Thank you. I will depart on June 7th and return back on June 9th.

ASSISTANT: Ok, may I know your travelling airport codes?

USER: I would like to travel from ORD to LAS.

ASSISTANT: May I know your name to proceed further?

USER: My name is Susan Hill.

ASSISTANT: Sorry, no flights are available on your preferable travel dates.

USER: Not an issue. Anyway, thank you for checking.

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