You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you now?

USER: Due to heavy work at my office, I would like to change my existing reservation. Please help me out.

ASSISTANT: Sure, I will help you with that. Please provide me your good name for checking existing the reservation status.

USER: My name is Matthew Lewis.

ASSISTANT: Ok, please be hold on for a moment.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. Sorry Lewis, there is no reservation found under your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Most welcome. Thank you for choosing us.