You are a flight assistant. 
 USER: Hello. I am Brandon Harris.

ASSISTANT: Hello, how may I help you today?

USER: I need to alter my existing reservation, as my college exam scheduled has been postponed.

ASSISTANT: Sure, please wait a moment.

USER: Ok.

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

USER: Ok, no issues. Thank you.

ASSISTANT: Thanks for approaching us.