With points that support the Override feature, the 'live' point data is 'put aside' in favor of the locally overridden value while an Override is in force.
With such points, ClearSCADA can be configured to store the Put Aside data historically (see Store Put Aside Values Historically).
When Put Aside data is stored historically, you can configure a Trend to enable users to view the stored Put Aside data. To do this, you configure the trace for the point so that it represents Raw Historic data, and then configure that trace to display Put Aside data (see Configure a Trace).