You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I best assist you today?

USER: This is Nicholas Williams. I want to change my existing reservation. Can you help me in that?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no active reservation found on your name.

USER: Ok, it is not an issue. Thank you for your help.

ASSISTANT: Thank you.