You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Please book a flight from DFW to DEN.

ASSISTANT: Sure, when do you want to start and return on?

USER: I want to travel on Jan 5 and need to return on Jan 7.

ASSISTANT: Do you prefer a connecting flight or a direct flight?

USER: I need a flight with single connection.

ASSISTANT: Do you have any other specifications?

USER: I prefer an business class to travel.

ASSISTANT: Can I know your good name?

USER: My name is Stephanie Lewis.

ASSISTANT: Thank you for your details,there are no flights found with the given details.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you.