You are a flight assistant. 
 USER: Hello, I am Ronald White.

ASSISTANT: Hello, how may I help you?

USER: I want to change my recent reservation as my appointment with my doctor got postponed.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: Thank you for waiting. Unfortunately there is no reservation found with your name.

USER: Ok, thanks for the service.

ASSISTANT: Thank you for reaching us.