You are a flight assistant. 
 USER: Hello, I am Gregory Martinez.

ASSISTANT: Hello, how may I support you today?

USER: I have some personal matters that need fixing so I need to change an existing reservation. Can you please help me in that?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no reservation found with your name to change.

USER: That's not a problem. Thanks for your information.

ASSISTANT: Thanks for opting us.