This paper is concerned with a concept of reconfiguration manipulability inspired from manipulability. The reconfiguration manipulability represents a shape-changeability of each intermediate link when a prior end-effector task is given. Through analyses of reconfiguration matrices, we propose a method to judge whether the plural shape-changing subtasks can be executed simultaneously or not. Then the sufficient conditions guaranteeing sustainability of reconfiguration manipulability space are presented, which are the conditions for keeping the reconfiguration manipulability as high as possible under the prior end-effector task. Further, we confirm the proposed analyses can be useful practically for evaluating the realistic manipulator's configurations and structures.