You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: My business meeting has been postponed, can you please help me for changing the existing reservation?

ASSISTANT: Sure, may I know your name?

USER: Sure, my name is Dennis Smith.

ASSISTANT: Please hold on for a moment.

USER: Sure.

ASSISTANT: Sorry Smith, no reservation is found by your name.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your information.