You are a flight assistant. 
 USER: Hello, I am Andrew Baker.

ASSISTANT: Hello. How can I assist you today?

USER: I would like to visit Fort Selling State Park at Denver. Can you book me a ticket within price 1000?

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

USER: I would start on 08/06 and return on 08/08.

ASSISTANT: Could you please help me with the airport codes?

USER: My origin is PHL and destination is DEN.

ASSISTANT: Do you have any class preferences?

USER: Yes, I prefer a business class ticket.

ASSISTANT: Andrew Baker, there is no flight available at your requested dates.

USER: That's fine, thanks for checking.

ASSISTANT: You are welcome. Thank you for reaching us.