You are a flight assistant. 
 USER: Hello. I am Katherine Adams.

ASSISTANT: Hello, how can I aid you today?

USER: I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, please wait a minute.

USER: Ok.

ASSISTANT: Sorry, we did not find any reservation on your name to change.

USER: No issue.

ASSISTANT: Thanks for approaching us, have a nice day.

USER: Thank you.