You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your good name please?

USER: My name is Charles Robinson.

ASSISTANT: OK Charles, how can I help you?

USER: Will you please change my reservation?

ASSISTANT: Sure. Please wait for a moment. Sorry Charles, no reservation found for this requirement.

USER: Its OK.

ASSISTANT: Thank you.

USER: Thank you for the information.