You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you at this moment?

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

ASSISTANT: Sure, can I know your departure and arrival travelling dates?

USER: My travel dates are from Sept, 09 to Sept, 11.

ASSISTANT: Ok, Please tell me your class preference.

USER: I do not have any class preferences.

ASSISTANT: Ok, do you need a lay by in between the journey?

USER: I need a single connecting flight.

ASSISTANT: Ok, may I know your good name please?

USER: Nicole Brown.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: There are no flights found on your requested dates.

USER: Thank you for your information.

ASSISTANT: Thank you for reaching us.