You are a flight assistant. 
 USER: Hello. I am Eric Hall.

ASSISTANT: Hello, how may I aid you today?

USER:  I want to change my reservation due to prepone of my meeting.

ASSISTANT: Sure, we are here to help you. Please hold a moment, let me check your reservation and let you know. Thanks for your time, unfortunately no reservation found with provided name.

USER:  Ok, thank you for your response.

ASSISTANT: Thank you for opting us.