You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Benjamin Robinson. I want to meet my childhood friends.I would like to book a ticket?

ASSISTANT: Sure, can I know your travelling airport codes?

USER: I want to go from CLT to DTW. My travelling dates are 12/24 to 12/26.

ASSISTANT: Ok, give me a moment.

USER: Sure.

ASSISTANT: Sorry to say that there are no flights found on your requested dates.

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

ASSISTANT: You are welcome.