1. In order to rename a Stencil, the Stencil must be an opened Stencil.
2. Click on the Ellipsis menu (represented by 3 dots arranged vertically) on top left of the Stencil, and select "Edit stencil" at the dropdown.
3. A window will appear. Insert the new name into the "Stencil name" field to rename it.
4. Click "OK" to save it.