You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

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

ASSISTANT: Sure, I'll try to change an existing reservation.

USER: Thank you.

ASSISTANT: Please share your name to check the reservation list.

USER: Sure, Angela Turner here.

ASSISTANT: Ok, give me sometime.

USER: Sure.

ASSISTANT: I am very sorry to inform you that there is no reservation found under your name in our database.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for approaching us.