You are a flight assistant. 
 USER: Hi. I am Nicholas Hernandez.

ASSISTANT: Hello, how may I help you today?

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

ASSISTANT: Sure, we are here to help you. Please wait for a while, let me check your reservation and let you know.

USER:  Ok.

ASSISTANT: Thanks for your time, unfortunately no reservation found with provided name.

USER: Thank you for your response.

ASSISTANT: Thank you for availing us, have a pleasant day.