The transition becomes a substitution transition and the newly created page is set as subpage, using the selected transition as substitution transition.
All places surrounding the transition are copied to the new subpage, and are set as ports.
All these ports are assigned to their counterparts (which become sockets) on the superpage.
The tool may also be applied to a closed group, as defined in Top-down development, to move the grouped net structure to a subpage. The group may not contain state space nodes or state space arcs.