This paper describes an extension of the pUML OO meta modelling approach to the re-architecting of the UML with dynamic aspects. It is based on both the MML and the Action Semantics, and shows the feasibility of the definition of the concepts in the Action Semantics using the pUML approach. Four packages are defined that extend the packages of MML: dynamicCore, actions, messaging, and compoundActions. The dynamicCore package defines the concepts Snapshot, SlotBinding and History. A definition of primitive actions, i.e. actions that are atomic, can be found in the actions package. Actions are defined as methods that (may) have an effect on the snapshot of the executing object. The concept compoundAction models the composition of actions into more complex dynamic structures. It includes GroupAction, ConditionalAction, and LoopAction. The messaging package defines actions that exchange messages between objects. It includes Signal, SendAction, and ReceiveAction. These four packages form the core of the rearchitecting of the Action Semantics in terms of the MML.