You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you today?

USER: I am Barbara Perez. I want to change my reservation due to sudden prepone of my cousins party.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

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

USER: Thank you for giving your information.

ASSISTANT: Thanks for opting us.