You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I am Helen Davis, can you make change in my existing reservation?

ASSISTANT: Sure, I will help you with the change of flight reservation.

USER: Thank you.

ASSISTANT: Thanks for waiting. But I am sorry to say that there is no flight reservation on your name to change it.

USER: It's ok, thanks for checking.

ASSISTANT: Thank you.