In any visible render layer, select a node, then right-click any attribute in its Attribute Editor to create an absolute or relative override.
Create overrides for the selected collection in your visible render layer
The override is automatically created beneath the collection.
Create overrides for a specific node in your visible render layer
A collection that contains the node is automatically created in the visible layer, as well as its corresponding override. For easy identification, the collection is, by default, named with the pattern _nodeName_col.
You can enable and disable an override by clicking on the override. This allows you to easily experiment with the effects of different overrides.
You can also create overrides by middle-mouse dragging and dropping an attribute into the Property Editor. See also Create overrides for a collection in your render layer.
In addition to creating overrides for an object or node currently in your visible render layer, you can also create overrides for a node currently outside of your visible render layer and add it to the visible layer in one step.
A collection that contains the node is automatically created in the visible layer, as well as its corresponding override. In other words, the node has also been added to the visible layer.
After creating the override, a red border may appear around the layer visibility icon to reflect that your layer information has changed. Click the icon for the overrides to be reflected in the viewport or in your render.