You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you?

USER: I want to go for a Twilight Tour with my friends on 06/23 and return on 06/25. Can you book a flight ticket?

ASSISTANT: Sure, may I know your price limit?

USER: 5000 is my airfare.

ASSISTANT: May I know your name please?

USER: Myself Susan Mitchell.

ASSISTANT: Can you please provide me your source and destination airport codes?

USER: Sure, my source point is NC - CLT and destination point is DC - IAD.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flights found with your given details.

USER: Ok, thank you for the information.

ASSISTANT: Thanks for choosing us.