thing changing possession relates an event (more specifically, an instance of change in user rights) to an object (an instance of thing existing stably in time) the user rights to which are transferred during that event. (thing changing possession EVENT OBJECT) means that in EVENT, all or some rights to use OBJECT are transferred from one agent (the originator) to another (the recipient). Since EVENT is an instance of change in user rights, it could be (among other things) a buying, renting, lending, or repossessing.