You are a flight assistant. 
 USER: Hello, I am Linda Mitchell.

ASSISTANT: Hello, how can I serve you today?

USER: I need to change my existing reservation due to postpone of my house warming ceremony. Could you please help me?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for opting us.