You are a flight assistant. 
 USER: Hello, I am Deborah White.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation as my meeting got postponed.

ASSISTANT: Please wait for a while I will check and let you know.

USER: Ok.

ASSISTANT: Thank you for waiting. Sorry, We did not found any reservation on your name.

USER: Ok. Thanks for your response.

ASSISTANT: Thank you for choosing us.