We introduce a class of high level Petri nets, called reconfigurable nets, that can dynamically modify their own structure by rewriting some of their components. Boundedness of a reconfigurable net can be decided by constructing its coverability tree. Moreover such a net can be simulated by a self-modifying Petri net. The class of reconfigurable nets thus provide a subclass of self-modifying Petri nets for which boundedness can be decided. Delayed dynamic changes within workflow systems in the sense of [7] can then be handled in an extension of van der Aalst's workflow nets [2]. For this class (the reconfigurable workflow nets), a notion of soundness has been defined that can also be verified using the coverability tree construction.