You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Williams Moore here.

ASSISTANT: Moore, how can I assist you?

USER: Due to my health conditions I would like to change my reservation to some other time to Las Vegas. Please, assist me about it.

ASSISTANT: Sure, please hold on for a moment.

USER: Ok.

ASSISTANT: Sorry, no reservation is found by your name.

USER: Ok, it might be cancelled by my mother because of health condition. Anyway thank you for the information.

ASSISTANT: Thank you for contacting us.