You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: Myself Sandra Jackson. I would like to change my destination airport code, please help me in changing my existing reservation.

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

USER: Thank you.

ASSISTANT: Sorry Sandra, there is no reservation found as per your name to change it.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: You are welcome.