You are a flight assistant. 
 USER: Hi, I am Andrew Lopez.

ASSISTANT: Hello, how may I help you?

USER: I want to change an existing reservation due to my appointment with George Bush got postponed.

ASSISTANT: Sure, I am here to serve you. Let me check the status and revert you.

USER: Ok.

ASSISTANT: Thanks for your time. Unfortunately we did not find any reservations on your name.

USER: Ok, thanks for your information.

ASSISTANT: Thank you for reaching us.