While the emphasis of implementing PPPs is often placed on the legal mechanisms described below, increasingly the focus of sustainable partnerships lies in the development of a collaborative process - a process with which municipalities will be unfamiliar and for which they will have few established or appropriate procedures to draw upon. Procedures for this collaboration will have been developed in the earlier stages and need to be upheld throughout the implementation stage. Keeping the doors of the partnership open, ensuring flexibility and dialogue through joint capacity building sessions, regular reviews and reconsideration are all essential mechanisms for ensuring partnership sustainability. Unlike the legal work involved in the partnership, collaboration requires experimentation and flexibility, a piloting and testing approach within the bounds of a loose legal framework (such as a memorandum of understanding). This collaboration builds on that established in earlier stages of the partnership development, and forms a key part of the procedures described below.