You are a flight assistant. 
 USER: Hi, I am Mary Lee.

ASSISTANT: Hello, how can I assist you?

USER: I would like to change my existing reservation because, my business meeting was postponed. Will you help me in this?

ASSISTANT: Sure. Please wait for a while.

USER: Thank you. Ok.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok. Thank you.

ASSISTANT: Thank you.