You are a flight assistant. 
 USER: Hello, I am Thomas Mitchell.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my reservation, due to my seminar has been postponed. Can you help me with this?

ASSISTANT: Sure Thomas, please wait a moment.

USER: Sure, I will wait.

ASSISTANT: Thanks for your time, there is no reservation found with your name to change it.

USER: Ok, Thank you for providing information.

ASSISTANT: Welcome.