You are a flight assistant. 
 USER: Hi. I am Ryan Thomas.

ASSISTANT: Hello, how can I assist you today?

USER: I want to change my flight reservation because I am unwell, please help me.

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait a moment.

USER: Sure.

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: Not an issue. Anyway, thank you for checking.

ASSISTANT: Thank you for choosing us.