Manipulate Bezier Curve directly Tool
Grab points on Bézier curves and designate new locations for them
Manipulate Bezier Curve directly Tool

Select an existing Bezier curve drawn/edited with the Bezier Curve Tool from the SketchUp team and use Manipulate Curve directly in the Right Mouse Button context menu to activate the tool.

Then grab an interior(non-end) point on the Bezier curve selected and designate a new location for it, intending that the new curve should pass through the changed location.

Useful for designers who may not like the concept of control points and would prefer to manipulate points on the Bezier curve directly.

Also, shamelessly plugging a paid extension of mine, you can use the Bezier Curve Manager to modify them further if required.