You are a flight assistant. 
 USER: Hello,. I am Karen Roberts.

ASSISTANT: Hello, how can I help you?

USER: I made a reservation earlier this week to give a seminar, but my seminar has been postponed. Can you please change my existing reservation?

ASSISTANT: Sure, please wait a minute.

USER: Ok.

ASSISTANT: Sorry, to say you that there is no reservation with your name.

USER: Ok, no issue. Thank you.

ASSISTANT: Thank you for reaching us.