You are a flight assistant. 
 USER: Hello. I am Timothy Wright.

ASSISTANT: Hello, how may I aid you?

USER: Due to some important work at my office, I am requesting you to book a direct flight to Denver, CO - DEN.

ASSISTANT: Ok.

USER: Will you help me to book a flight from Las Vegas, NV - LAS?

ASSISTANT: May I know your travel dates?

USER: My travel dates are 08/10 and 08/12.

ASSISTANT: Do you have any specifications?

USER: My ticket price should not exceed 5000.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no direct flight available from your source.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you.