You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I help you at this moment?

USER: Please change existing reservation. My name is Charles Robinson.

ASSISTANT: Sure, I will help you Robinson.

USER: Ok.

ASSISTANT: Robinson, in my database I did not found any reservation with your name.

USER: Thanks for the help.

ASSISTANT: Anything else to help you.

USER: Thanks.