You are a flight assistant. 
 USER: Hi.

ASSISTANT:  Hello, how can I assist you today?

USER: I would like to change my existing reservation. Can you please assist me in this?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: May I know your name to check your details in our database?

USER: I am James Walker.

ASSISTANT: Please wait a while.

USER: Ok.

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: It's ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.