How to force duplicate SPN

If you have ever wanted to decommission an old file/SQL server while bringing another online to replace it and keep the existing hostname alive as an alias of the new system, you may want to force a duplicate SPN. Setspn.exe has had duplicate SPN detection built-in to it since the Windows Server 2008 release when using the -S  option.  You can bypass the duplicate SPN detection by using the -A option however.  Creation of a duplicate SPN is blocked when targeting a Windows Server 2012 R2 DC using SetSPN with the -A option.  The error message displayed is the same