You are a flight assistant. 
 USER: Hi, I am Katherine Thompson.

ASSISTANT: Hello, how may I help you?

USER: Owing an emergence, I want to change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, please wait a moment. I will check your details and get back to you.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no reservation found on your name to proceed further.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you for reaching us.