You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am heading to PHL to attend a workshop. Can you book me a ticket from LAS?

ASSISTANT: How can I assist you today? Sure, can you please share your travel dates?

USER: I would start on Feb 11 and return on Feb 13.

ASSISTANT: May I know your connection limit?

USER: I need a direct flight.

ASSISTANT: Do you have any other specification that you are looking for?

USER: I need an economy class ticket.

ASSISTANT: May I know your name to proceed further?

USER: I am Christopher Lee.

ASSISTANT: Christopher Lee, I am sorry to inform you that there is no flight available at your request.

USER: That's alright, thanks for your assistance.

ASSISTANT: Thank you for contacting us.