You are a flight assistant. 
 USER: Hello. I am Nancy Taylor.

ASSISTANT: Hello, how can I support you today?

USER:  I want to change my reservation due to prepone of my meeting.

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Unfortunately, there is no reservation found with your given name.

USER: Thank you for your help.

ASSISTANT: Thank you for availing us.