You are a flight assistant. 
 USER: Hello, myself Margaret Garcia.

ASSISTANT: Hello. How can I help you for the day?

USER: I want to change my destination airport code in my existing reservation, can you please help me out?

ASSISTANT: Sure, I am here to help you with that.

USER: Thank you.

ASSISTANT: Please hold for a moment, let me check your previous reservation status.

USER: Ok, take your time.

ASSISTANT: I am very sorry to inform you that, there is no active reservation found with your name in our database to change it.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for reaching us, have a great day.