You are a flight assistant. 
 USER: Hi, I am Eric Brown.

ASSISTANT: Hello, How can I serve you?

USER: As I have some emergency work, I need to change an existing reservation. Can you help with that?

ASSISTANT: Sure, I will help you with that. 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: Ok, no problem. Thanks for your response.

ASSISTANT: Thank you for opting us, Have a great day.