You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I abet you?

USER: I am Sandra Jones. Owing to an emergency, I want to change an existing reservation. So please help me in changing the reservation.

ASSISTANT: Sure, we are here to help you. Please stand by.

USER: Sure.

ASSISTANT: Unfortunately, there is no active reservation on your name to proceed further.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for choosing us.