You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: Owing to emergency I want to change my reservation, can you help me?

ASSISTANT: Sure, may I know your good name please?

USER: My name is Mary Adams.

ASSISTANT: Sorry, there is no previous reservation found on your name to change.

USER: That's fine.

ASSISTANT: Thank you for approaching us.

USER: Thank you for checking.