You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Can you help me to book a flight ticket from PHL to DFW?

ASSISTANT: Sure, may I know your travel dates?

USER: My travelling dates are 13 and 15 of July.

ASSISTANT: Do you have any class preferences on your journey?

USER: I prefer to travel in business class.

ASSISTANT: May I know your name for the documentation purpose?

USER: I am Kevin Campbell.

ASSISTANT: Do you have any another preferences on your trip?

USER: I need a connecting flight.

ASSISTANT: Unfortunately, no flights available on your requirements.

USER: It's ok, not a problem, thank you.

ASSISTANT: Welcome, thank you for reaching us.