You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can we help you?

USER: Owing to an emergency, I want to change my existing reservation.

ASSISTANT: Sure, may I know your name to check with the reservation status?

USER: Sure, Catherine Collins here.

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

USER: Ok, no worries at all. Thank you for your information.

ASSISTANT: Thank you for reaching us.