You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: I just want to change an existing reservation as my meeting got post pone due to some technical issues. Can you help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: Nicholas Evans.

ASSISTANT: There is no reservation found under your name to change.

USER: No issue, Thank you for the information.

ASSISTANT: Thank you for choosing us.