Altering table on SQL Server 2012 AON High Availability Databases
It turns out that changes in table structure (schema) is automatically handled, so changes in the primary database should be also reflected in the secondary ones.


  Schema changes and data changes are essentially the same. It works like traditional mirroring today : what happened in the log on the primary happens on the secondary. Not everything that happens in Vegas has to stay in Vegas. :-)


Source: Do schema changes &quot;break&quot; SQL Server 2012 AlwaysOn or are they handled transparently?