You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: Can you help me in booking a flight ticket from LGA to DEN?

ASSISTANT: Sure, can you please mention with your dates of journey?

USER: I want to travel on 04/19, and return on 04/21.

ASSISTANT: May I know your good name please?

USER: I am Benjamin Johnson.

ASSISTANT: Are you looking for any other help from my side please?

USER: I prefer for business class.

ASSISTANT: Please wait for a mean while.

USER: Sure.

ASSISTANT: Sorry Johnson, there is no flight found as per your travelling details.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: You are welcome.