You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I am planning to change my reservation, can you help me in that?

ASSISTANT: Sure, I can help you with that. May I know your good name please?

USER: I am Charles Carter.

ASSISTANT: Charles Carter, there is no active reservation found under your name to do changes in that.

USER: That's ok, thank you.

ASSISTANT: Thank you for choosing us, have a nice day.