ChangeDegree is good when inserting knots/control points to single span curves and surfaces if the desire is to retain a single span curve or surface…

InsertKnot or InsertControlPoint are the better commands to use to add knots and control points to a mult-span curve or surface while retaining the degree of the curve or surface.

The results of ChangeDegree may be different than what is desired shen starting with a multi-span curve or surface. When increasing the degree with ChangeDegree if Deformable=No is used then the result is higher degree multi-span curve with multiknots betwen the spans which exactly the same continuity between spans the the original lower multi-degree curve. The increase in the number of control points will be equal to the difference in degree multiplied by the number of spans. I have not found a use for this result in my work. In the same situation but with Deformable=Yes the number of control points will be increased by the difference in degree, independent of the number of spans but the shape of the curve or surface will usually be changed.