You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you the day?

USER: Due to health issues, I want to change my existing reservation. Can you help me with it?

ASSISTANT: Sure, I am grateful to help you. Please specify your name to proceed further?

USER: My name is Patrick Hernandez.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

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

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you for approaching us regarding reservation changing process.