You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I want to book a flight ticket from DEN to attend a robotic workshop in JFK, can you help me in booking?

ASSISTANT: Sure, We are here to help you. Can I know your travelling dates?

USER: I intend to start on may 21st and my return date will be on May 23rd.

ASSISTANT: Do you need any break?

USER: Yes, I need a break.

ASSISTANT: Is there any other specifications?

USER: I want to depart in the afternoon. I prefer economy class ticket.

ASSISTANT:  Ok, Give me a minute.

USER: Sure.

ASSISTANT: Unfortunately, there are no flight found according to your requirement.

USER: No issues, I'll choose any other alternative to reach my destination. Thank you.

ASSISTANT: May I know your name?

USER: I am Robert Thomas.

ASSISTANT: Thank you for choosing us.

USER: Thank you.