You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, I can help you with that. May I know your good name please?

USER: Alexander Johnson here.

ASSISTANT: Alexander Johnson, there is no active reservation found under your name to do changes in that.

USER: No problem, thanks for the information.

ASSISTANT: Thank you for choosing us.