You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you today?

USER: There is a slight change in my existing reservation, can you please help me?

ASSISTANT: Sure, I am here to help you. Can you mention your name to check further?

USER: Sure, myself Brian White.

ASSISTANT: Please wait.

USER: Sure, I will wait.

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

USER: No issue, anyway thank you for checking.

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