This paper describes a modification method which strengthens forms for deriving diverse design solutions in structural design. In the early process of design, diverse design ideas are generated from a global solution search under unclear design conditions. In the past study, we have proposed the emergent design system, which allows a global solution search under limited design conditions to derive diverse design solutions. The proposed system derives geometrically novel in forms, but most of them do not satisfy the evaluation standard so that they are not applicable as solutions. Therefore, if we can modify these forms to applicable solutions, the diversity of applicable solutions would increase. In this paper, we propose a modification method which satisfies the evaluation standard by increasing and decreasing elements, and show the possibility of increasing the diversity of solutions.