You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I support you today?

USER: Owing to an emergency, my appointment with doctor has been postponed. So I had a request to you to change my existing reservation?

ASSISTANT: Sure, May I know your name please?

USER: Sure, I am Cynthia Hernandez.

ASSISTANT: Ok, Cynthia Hernandez, please wait for a minute.

USER: Sure.

ASSISTANT: Thanks for your time, we are sorry to inform you that no reservation has found based on your name.

USER: Ok, no issues. Thanks for your valuable information.

ASSISTANT: Thanks for availing us. We hope to serve you again.