You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: Can you please change my existing reservation? Because I need to attend to an emergency meeting at other place.

ASSISTANT: Sure, let me know your good name please.

USER: So, please change my reservation which is reserved under my name Mary Allen.

ASSISTANT: Ok,  please wait a while.

USER: Ok.

ASSISTANT: Thank you for your time. Unfortunately there is no reservation found by your name.

USER: Ok, Thanks for sharing the valuable information.

ASSISTANT: Thank you for availing us.