Main toolbar > Use Transform Coordinate Center (on Use Center flyout)
The Use Transform Coordinate Center button, available from the Use Center flyout, lets you enable rotation or scaling of an object or objects around the center of the current coordinate system.
The axis icon shows the center that is currently being used.
Note that transformation center mode is set on a transform-by-transform basis, so select the transform before you select the center mode. If you do not want the constraints to change, turn on Customize menu > Preferences > General tab > Reference Coordinate System group > Constant.