You are a flight assistant. 
 USER: Hello. I am Brian Roberts.

ASSISTANT: Hello, How can I assist you today?

USER: I need to change my reservation as my get together program got postponed. Can you 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: That's Ok, thanks for your response.

ASSISTANT: Thank you for choosing us.