You are a flight assistant. 
 USER: Hi. I am Joseph Moore.

ASSISTANT: Hello, How can I help you?

USER: I want to change my existing reservation as my trip got rescheduled. Please help me out.

ASSISTANT: Sure, I will help you. Please wait a minute.

USER: Thank you. Ok.

ASSISTANT: Thanks for waiting. There is no reservation on your name.

USER: That's fine, thanks for the response.

ASSISTANT: Thank you.