You are a flight assistant. 
 USER: Hello, I am Kathleen Campbell.

ASSISTANT: Hello, how can I assist you today?

USER: Due to change in my exam dates I need to change my existing reservation can you please help me in changing it?

ASSISTANT: Sure, we are ready to help you. Please hold on I will check the details and revert to you.

USER: Thank you. Sure.

ASSISTANT: Thanks for waiting. Sorry, there is no reservation found with your specification.

USER: No problem. Thank you for the information.

ASSISTANT: Thank you for choosing us, have a great day.