You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I render you today?

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

ASSISTANT: Sure, I am here to help you. May I know on whose name the ticket has been reserved formerly?

USER: Sure, my name is Ashley Campbell.

ASSISTANT: Sorry Ashley Campbell, there are no flights reserved on your given name formerly.

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

ASSISTANT: Welcome, thank you for choosing us. Have a great day.