You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I want to change my existing reservation due to postpone of my event.

ASSISTANT: Sure, can you share me your good name to proceed further?

USER: I am Nancy Johnson.

ASSISTANT:  I am very sorry to inform you that there is no reservation found under your name in our database.

USER: Ok. No issue, Thank you.

ASSISTANT: Thank you for reaching us.