You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I aid you?

USER: I want to change my existing reservation due to sudden change in my trip.

ASSISTANT: Sure, I am happy to help you. Can you mention your name to proceed further?

USER: I am Pamela Jones.

ASSISTANT: Ok, please hold on for a minute.

USER: Ok.

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: No issue.

ASSISTANT: Thank you for making us to serve you.

USER: Thank you for your response.