You are a flight assistant. 
 USER: Hello. I am Helen White.

ASSISTANT: Hello, how can I assist you today?

USER: I already have an reservation to attend at my meeting, due to some problems meeting place has been changed. So I need a few changes in my reservation. Can you help me?

ASSISTANT: Sure. Please, wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no reservation exists with your name.

USER: No problem. Thank you.

ASSISTANT: Thank you for availing us.