The increasing dependency of society on electricity motivates the research for more reliable and resilient distribution networks. Self-healing of networks is one of the key elements of the Smart Grid concept. Conventional self-healing networks (CSHNs) recover part of the network by rerouting power with automated switchgear. By utilizing microgrids (MGs), the sectionalizing distribution networks (SDNs) concept is an extension of CSHNs which utilizes both automated switchgear and distributed energy resources (DERs) to create both grid-connected and islanded microgrids (MGs). The SDN concept provides more resilience against faults than CSHNs and allows local bottom-up blackout restoration. This paper provides a high-level conceptual and operation states description, a system framework and the operational sequence of SDNs in case of faults. Finally, several future research directions are proposed.