You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I want to change my existing reservation, as my health is not good. Can you please help me out with it?

ASSISTANT: Sure, Let me know your name to check your reservation?

USER: Thank you for the response, Karen Rodriguez is my name.

ASSISTANT: Ok, please wait a moment.

USER: Ok, sure. I will wait for your response.

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: Ok. Not an issue. Thank you for the information.

ASSISTANT: Thank you for choosing us.