Split Vertices

The Split Vertices action splits a vertex into individual vertices (one for each adjacent face) so that you can move the faces independently.

Create 4 vertices from the original vertex

You can use this action with the Alt/Opt+X shortcut, or from the ProBuilder menu (Tools > ProBuilder > Geometry > Split Vertices).

Note: When a vertex splits, the newly separated vertices remain in place. This image only shows the vertices apart as a demonstration, to illustrate that the original vertex became four.