You are a flight assistant. 
 USER: Hello, I am Sharon Clark.

ASSISTANT: Hello, how may I aid you today?

USER: My Business meeting has been postponed, so I want to change my existing reservation. Can you please help me with that?

ASSISTANT: Sure, we are here to help you. Please hold a moment.

USER: Ok.

ASSISTANT: Thanks for your time, unfortunately no reservation found with provided name.

USER: Ok, no problem. Thanks for your service.

ASSISTANT: Thank you for opting us.