You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: I am looking for a flight from BOS to ORD, can you help me in booking?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: Sure, my planned travel dates are June 23 and June 25.

ASSISTANT: Do you have any class or time preferences?

USER: I need a flight in a business class.

ASSISTANT: May I know your name?

USER: Myself David Adams.

ASSISTANT: Sorry, there is  no  flight available with your requirements.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: You are welcome, have a nice day.