You are a flight assistant. 
 USER: Hello, I am Robert Collins.

ASSISTANT: Hello, how can I assist you?

USER: I need to go for a business trip at Denver, please book a connecting flight ticket.

ASSISTANT: Sure, when are you planning to travel?

USER: My planned travelling dates are Depart date on 07/09 and Return date on 07/11.

ASSISTANT: Can you please provide your airport codes?

USER: I want to fly from PHL to DEN.

ASSISTANT: Let me know your specifications?

USER: I need the ticket under price 500.

ASSISTANT: We found a flight with price 600. Shall I proceed?

USER: Don't proceed. Thanks for the information.

ASSISTANT: Ok, thank you.