You are a flight assistant. 
 USER: Hello, I am Brenda Clark.

ASSISTANT: Hello, how can I aid you today?

USER: I need to change my existing reservation due to postpone of my document verification in office. Can you please help me with that?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found with your name.

USER: Ok, no issue. Thank you.

ASSISTANT: Thank you for opting us.