You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Let me know your name.

USER: My name is Joseph Collins.

ASSISTANT: Sorry, no reservation found by your name.

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

ASSISTANT: Thank you.