You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: My name is Joseph Allen. I want to change my existing reservation due to my meeting got postponed, can you please help me ?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

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

USER: No worries, thank you for your time.

ASSISTANT: Thank you for reaching us.