You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I want to change my existing reservation. Can you help me for that one?

ASSISTANT: Sure, may I know your good name please? Please wait for a moment.

USER: Sure,Carolyn Turner here. Sure.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: No issues, thank you for the information.

ASSISTANT: Thank you for approaching us.