You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kenneth Allen.

ASSISTANT: How can I help you?

USER: Can you search for a flight for me from CLT to DFW?

ASSISTANT: Let me know your travelling dates in order to book a ticket.

USER: Ok, my travel dates are from Mar 20 to 22.

ASSISTANT: Do you have any preferences?

USER: Ok, I need a flight in business class.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: It's ok, thanks for your information.

ASSISTANT: Thank you.