In this paper we introduce an approach to software process modeling and execution based on the distinction between an application level (oriented towards a comprehensive representation of software process models) and an intermediate level representation of software process models (oriented towards uniform and executable description of software process models). The application level representation of software models identifies various entities of software process models. For describing different entities of software process models different views are used. The entities specified within all the views are uniformly represented on the intermediate level by FUNSOFT nets. FUNSOFT nets are high-level Petri nets which are adapted to the requirements of software process management. A mechanism for coping with software process model modifications raised in software process execution is introduced. This mechanism is based on modification points. Moreover, we discuss the architecture of the environment MELMAC which supports software process modeling as well as software process execution.