The Work-as-a-Service (WaaS) paradigm models work engagements as compositions of interconnected service requests, where there is a separation between the coordination of work and the actual work enactment. Here we revisit the WaaS conceptual meta-model and extend it to enable work decomposition and adjustable management/control of how work is coordinated and how it is done. In particular, we propose a specific WaaS protocol for decomposition, delegation, and control of work engagements, using ideas from the area of Business Artifacts. The goal is to enable simple communication and coordination between requestors and providers of work; and to support clear management and coordination during both planning and enactment of work. Importantly we introduce a new notion of a coordination lifecycle, consisting of loosely coupled milestones, domain-specific information attributes, and sets of abstract observable activities to be performed. Algebraic operations on coordination lifecycles when encapsulated service requests are torn, merged, paused, and resumed are defined and valid operations are specified. The meta-model and protocol are independent from the specific coordination enactment model which may employ centralized coordination, fully distributed coordination, or other models under various optimization objectives.