You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I want to change my existing reservation which I have done before due to booking of wrong destination in that ticket. Can you help me about it?

ASSISTANT: Ok, may I know your name to check please?

USER: I am Christopher Smith.

ASSISTANT: Please wait for a moment Christopher Smith. Sorry to inform you but there is no reservation found by your name Christopher Smith.

USER: Not an issue, thank you for the information.

ASSISTANT: Thank you for contacting our agency.

USER: Most welcome.

ASSISTANT: Have a great afternoon.