You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Please help me to book a flight ticket from PHL to DEN.

ASSISTANT: Sure, may I know the travelling dates?

USER: My trip dates are Aug, 13 and Aug, 15.

ASSISTANT: Do you have any connection limit?

USER: I would prefer single connection.

ASSISTANT: Is there any other requirements?

USER: No.

ASSISTANT: May I know your name?

USER: Mary  Baker.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, no flights found with your chosen dates.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for opting us.