You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: Help me in changing my previous flight reservation.

ASSISTANT: Sure, I am here to help you. May I know your name please?

USER: Larry Collins here.

ASSISTANT: Ok, please wait for a moment.

USER: Sure, take your time.

ASSISTANT: Sorry Larry, there is no reservation found as per your name to change it in your database.

USER: Ok, not an issue. Thanks for checking.

ASSISTANT: You are welcome.