You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Owing to an emergency, I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: We are here to serve you. Could you please provide me your name.

USER: Christine Green here.

ASSISTANT: Spare me a moment.

USER: Ok.

ASSISTANT: Christine Green, I regret to inform that there is no reservation by your name.

USER: Not an issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you.