You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jonathan Campbell.

ASSISTANT: How can I assist you today?

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

ASSISTANT: Sure, can you please share your travel dates?

USER: I am departing on June 13 and return on June 15.

ASSISTANT: Do you have any class preference?

USER: I am ok with any class.

ASSISTANT: Jonathan Campbell, I am sorry to inform you that there is no flight available at your request.

USER: That's ok, thank you for your information.

ASSISTANT: You are welcome. Thank you for reaching us.