You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: John Hernandez here. I am planning to travel from DEN to ATL, can you help in booking a flight for me?

ASSISTANT: Sure, I will help you with that. Can I have your travel dates please?

USER: My adte of travelling is on 12/02 to 12/04.

ASSISTANT: Please wait a moment and I will inform you flight details soon.

USER: Sure.

ASSISTANT: Sorry  John Hernandez, no flight is available to you on your dates.

USER: That's ok. Thank you for your help.

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