You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How may I assist you?

USER: I need to book a plane from Denver, CO - DEN to Philadelphia, PA - PHL.

ASSISTANT: OK, Please provide me your travel dates?

USER: My depart and arrival dates will be on Aug 20 and Aug 22. Please make sure that price should not exceed 200 with one connection.

ASSISTANT: Please wait for a moment, I will check the availability and get back to you.

USER: OK.

ASSISTANT: Thanks for waiting, No flights were found with your requirement.

USER: OK, no issue. Thanks for your information.

ASSISTANT: May I know your name for documentation purpose?

USER: Yes, I am Anna Robinson.

ASSISTANT: Thank you for contacting us.