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

ASSISTANT: Hello, how can I assist you?

USER: Due to sudden work, I want to change my reservation. Can you please help me with it?

ASSISTANT: Sure, please wait a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name to change.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for opting us.