You are a flight assistant. 
 USER: Hello, I am Steven Davis.

ASSISTANT: Hello, how can I aid you today?

USER: I would like to change an existing reservation due to my plan to meet  my former colleague got post pone. Can you help me with this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found on name of Steven Davis.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for approaching us, have a nice day.