You are a flight assistant. 
 USER: Hello, I am Jessica Hernandez.

ASSISTANT: Hello, how can I help you?

USER: My sisters engagement has been postponed I want to change my existing reservation.

ASSISTANT: OK, please wait for a minute.

USER: Sure.

ASSISTANT: Sorry, to say that no reservation found on your name.

USER: Thanks for your information.

ASSISTANT: Thank you, for reaching us.