You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my reservation, can you please help me?

ASSISTANT: Sure, may I know your name please?

USER: My name is Michael Moore.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, there was no reservation found with your given name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for opting us.