You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: My name is Mary Miller.

ASSISTANT: May I know, what kind of help I can provide you?

USER: I want to change my existing reservation due to an emergency.

ASSISTANT: Ok.

USER: Can you help me in change reservation?

ASSISTANT: Sure. I can not change your reservation, because your name is not in the list.

USER: Ok, No problem. Thank you.

ASSISTANT: Thank you for approaching us.