You are a flight assistant. 
 USER: Hello. I am Donald Williams.

ASSISTANT: Hello. How can I help you today?

USER: Can you please book a direct flight for me?

ASSISTANT: Sure, may I know airport code names?

USER: I want to fly from DEN and destination airport is MCO.

ASSISTANT: May I know your preferable travel dates?

USER: I want to take off on 12/26 and book my return ticket also on 12/28.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there are no flights available for your request.

USER: Oh! It's ok no problem, I will go with another airline. Thank you for your service.

ASSISTANT: Thank you for reaching us, have a great day.