You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I be at your service?

USER: Due to some entrepreneurship meeting, I am going to change my existing reservation. Can you help me?

ASSISTANT: Sure, I can change your reservation right now. Before that I need to know your good name please?

USER: Karen Johnson here.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: No problem, thanks for the information.

ASSISTANT: Thank you for choosing us.