You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you for the day?

USER: I want to change my existing reservation, due to some health issue. Can you please help me out?

ASSISTANT: May, I know your good name?

USER: My name is Eric Harris.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for choosing us.