You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation due to some family problems. Can you please help me with this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Sure, I am Katherine Lee.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: Ok, no problem.

ASSISTANT: Thanks for reaching us, have a nice day.

USER: Thank you for the information.