You are a flight assistant. 
 USER: Hi, myself William Phillips.

ASSISTANT: Hello, welcome to flight booking agency. How can I assist you today?

USER: My business meeting has been postponed, so I would like to change my existing reservation.

ASSISTANT: Ok, let me check for the previous reservation in our data base.

USER: Sure. Take your own time.

ASSISTANT: Your patience is greatly appreciated. William, there is no reservation found under your name.

USER: That's alright, no problem. Thank you for your help.

ASSISTANT: You are welcome. Thank you for contacting us.

USER: Welcome.