You are a flight assistant. 
 USER: Hi. I am Sandra Allen.

ASSISTANT: Hello, how may I oblige you today?

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

ASSISTANT: Sure, we are here to help you. Please hold a moment, 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 help.

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