You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. How shall I help you?

USER: I am Catherine Campbell. Owing to an emergency, I would like to change my existing reservation.

ASSISTANT: Ok.

USER: Can you help me out?

ASSISTANT: I'm sorry, no reservation found by name Catherine Campbell.

USER: Ok, not an issue.

ASSISTANT: Thanks.

USER: Thank you.