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

ASSISTANT: Hello Ronald Williams. How may I help you?

USER: I want to change my existing reservation as my meeting got postponed. Can you help me out with it?

ASSISTANT: Sure, I can help you with that. Wait a minute, I will check the status and revert you.

USER: Ok.

ASSISTANT: Sorry there is no reservation found with your name.

USER: Ok.

ASSISTANT: Thanks for contacting us.

USER: Thanks for the response.