You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I am planning to meet my colleagues who are staying in CLT, can you please assist me in booking a flight ticket from DFW?

ASSISTANT: Ok, may I know your journey dates?

USER: My journey dates are June 20th and June 22nd.

ASSISTANT: Do you have any other requirements?

USER: I prefer to travel in business class.

ASSISTANT: May I know your name in the meanwhile?

USER: Nancy Lopez.

ASSISTANT: Sorry Nancy Lopez, there is no flight running on your route.

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thanks for choosing us.