You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I made a reservation earlier in the wrong date unknowingly. Can you please change my existing reservation?

ASSISTANT: Sure, I am here to help you. May I know your name to check further in our database?

USER: I am Christopher Smith.

ASSISTANT: Please stand by.

USER: Ok.

ASSISTANT:  Sorry, no reservation found on your given name in our database to change it.

USER: Ok, Thank you.

ASSISTANT: Thank you for contacting us and have a nice day.