You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I am Mark Campbell. Please book a flight ticket on dates 11/11 and 11/13.

ASSISTANT: Sure, can you please share your source and destination airport codes?

USER: Yes, my airport codes are NY-JFK and IL-ORD.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER:          That's ok, thank you for the response.

ASSISTANT: Thank you for approaching us.