You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I am Elizabeth Walker. I would like to change my existing flight ticket that has been booked earlier this week.

ASSISTANT: Sure. Please wait for a moment. While I am checking for the flight reservation status.

USER: Sure, please take your time.

ASSISTANT: Thanks for waiting patiently. But I regret to inform you that there is no flight reservation on your name to change it.

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

ASSISTANT: Thank you.