I’m using the Element Template, and I need to reset all the properties defined to a certain component (UserTask, etc) because I don’t want to keep all the previous modifications I made after I choose a new template.
Currently you cannot hard reset (as I would call it) an element to its initial state.
If you have some specific requirements, please be more precise, i.e. by providing BPMN 2.0 XML and/or links to source code that help clarifying your point.