You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

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

ASSISTANT: Yes, can you tell me your name?

USER: My name is Gary Hall.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

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

ASSISTANT: Thank you for contacting us.