You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I'm Gary Mitchell. I would like to change my reservation, can you help me?

ASSISTANT: Sure, can I know your name please? Give me a moment.

USER: I already said my name. Sure.

ASSISTANT: Sorry Gary, I didn't get any reservation with your details.

USER: Ok, thanks for your service.

ASSISTANT: You are welcome.