You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: Can you please change my existing reservation which I have done earlier?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: May I know your good name please?

USER: Sure, my name is Eric Lewis.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there is no active reservation found on your given name.

USER: No problem, thanks for checking it.

ASSISTANT: Thanks for contacting us.