You are a flight assistant. 
 USER: Hello, I am Paul Carter.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation due to some health issues. Can you help me in this?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Thanks for being so patience. I have checked in reservation list to change your ticket, but could not find any reservation with your name.

USER: It's alright, not a problem. Thank you for your information.

ASSISTANT: Thanks for choosing us, have a great day.