You are a flight assistant. 
 USER: Hi, I am Justin Perez.

ASSISTANT: Hello, how can I help you today?

USER: I want to participate in a Havasupai adventure at Denver, CO - DEN. Can you help me to book a direct flight?

ASSISTANT: Sure, I will help you in booking a flight. Please share me your journey dates?

USER: I want to fly on 02/16 and return on 02/18.

ASSISTANT: May I know your budget for flight ticket?

USER: The price should not exceed 200.

ASSISTANT: Please provide me the source airport code?

USER: My source is at Austin, TX - AUS.

ASSISTANT: Ok. please wait for a while.

USER: Sure.

ASSISTANT: Thanks for your patience, sorry there is no any flight available on your journey dates.

USER: Ok, thanks for your service.

ASSISTANT: Thanks for reaching us, have a nice day ahead.