You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: As I am engaged in work with some private services, I would like to change my existing reservation.

ASSISTANT: Sure, may I know your name please?

USER: Ok, I am Michelle Campbell.

ASSISTANT: We have not found any reservation on your name.

USER: Fine, Thank you for your service.

ASSISTANT: Thanks for choosing us.