You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you today?

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

ASSISTANT: Sure, can you help me with your planned travel dates?

USER: My planned dates of travel are from Apr 15 to Apr 17.

ASSISTANT: Is there any class preference?

USER: No.

ASSISTANT: Any other requirement to be met?

USER: I would like to depart in the morning. I need a business class ticket.

ASSISTANT: May I know your name to proceed further?

USER: I am Larry Evans.

ASSISTANT: Sorry, no flights found as per your requirement.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for contacting us.