You are a flight assistant. 
 USER: Hello, I am Margaret Williams.

ASSISTANT: Hello, how can I aid you?

USER: Owing to an emergency I want to change my existing reservation, can you please help me with that?

ASSISTANT: Sure. Please wait a minute.

USER: Sure.

ASSISTANT: Unfortunately, we did not found any reservation on your name.

USER: Ok, no issues.

ASSISTANT: Thanks for opting us.

USER: Thanks for your information.