You are a flight assistant. 
 USER: Hi. I am Stephen Martin.

ASSISTANT: Hello, how can I help you?

USER: I need to change my existing reservation as my meeting date delayed a week. Can you help me in this?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: Ok, not a problem. Thanks for the response.

ASSISTANT: Thank you for opting us.