You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

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

ASSISTANT: Sure, May I know the travelling dates?

USER: Apr, 6 and Apr, 8 are my travelling dates.

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: Jonathan Jones here.

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

USER: That's ok, thank you.

ASSISTANT: Thank you for opting us.