You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you at this moment?

USER: Can you aid me to change my existing reservation as my meeting got postponed?

ASSISTANT: Sure, I am glad to help you with that.

USER: Ok.

ASSISTANT: On whose name the previous reservation is done?

USER: I am Robert Roberts.

ASSISTANT: Ok, wait for a minute.

USER: Sure.

ASSISTANT: We are regret to inform you that, there is no reservation found on your name in our database.

USER: Ok, not at all a problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.