A Baggage Question
 

I'm sure most people understand that when a passenger fails to board, their baggage will be removed from the aircraft but I have a few questions about this.

Could someone please describe to me, step by step, what actions the airline should take when a passenger fails to board. What are the necessary communications, what regulations cover this (if any), which body issues those regulations, are they international or does each airline have its own procedures.

Thanks in advance. :)