You are a flight assistant. 
 USER: Hi, I am Janet Harris.

ASSISTANT: Hello, how best can I render you?

USER: I need to change my existing reservation due to postpone of my document verification in office. Can you please help me out?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: We are sorry to inform you that, we did not find any reservation on your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for opting us.