You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Gregory Phillips.

ASSISTANT: How can I help you?

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

ASSISTANT: Sure, please wait for a while.

USER: Ok, take your time.

ASSISTANT: Sorry, there is no reservation found by your name.

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

ASSISTANT: Thank you and have a nice day.