When an occurrence of a recurring activity is modified, it becomes a 'variance'. Essentially it's a modified occurrence. Any modifications, including modifications to Start, End, Subject etc... cause the occurrence to be a variance.
ListScheduleDataConnector stores variances in the underlying data source list where recurring activities are stored. Note that to programatically modify an occurrence and make it into a variance and store it into the data source, you must call XamScheduleDataManager.BeginEdit and XamScheduleDataManager.EndEdit methods.
Note that IsOccurrence property will return true for variances as well.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2