You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: Sure, I have reserved a seat with my name Shirley Roberts.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok, thanks for sharing the information.

ASSISTANT: Thanks for contacting us, hope to serve you again.