Change Value is used to transform one value to another: For example, remapping a note's pitch, its velocity, a controller value, etc. Change Value does not transform one event type into another (use the Change Type FX for that).
A Wet/Dry control sets how much of the effected signal gets through.
The Source section allows you to control what event properties are altered. By default, note pitch is changed, but anything from the menu can be selected, or other FX can be dragged onto the source in case a desired option isn't available.
The shape view defaults to a simple map that replaces each value with itself, plus a small amount of noise. If we remove the noise (by clicking the D parameter button and dragging down) then we're left with a shape that effectively does nothing: Each 0-1 value is replaced with the same 0-1 value.
We can perform an inversion by setting the start (A) param to 1 and the end (B) param to 0.
Or we can just get crazy by selecting any of the available shapes, or directly editing this shape in the browser.
The Change Value shape view makes use of the current polarity: By default, the shape is unipolar, and performs a replace operation on each value. If you switch the polarity to bipolar, Change Value now performs a shift operation, offsetting each value based on the shape.
For example, in bipolar mode, a flat line is now the 'zero' state, where no processing is done: