This project is dealing with Centraal Beheer Office, designed by Herman Hertzberger, one of the most representative Structuralism Architects. Despite its architectural meanings and values, Centraal Beheer Office is now disconnected from its surroundings and possess various problems such as sustainability. Since Structuralism Architecture pursued architecture that could flexibly respond to the individual’s way of life and could transform itself based on the changing needs of users, this project also aimed to make a design experiment of balancing between preservation and modification in heritage design. Under the motto of ‘Returning to the Origin,’ this project considered the initial idea of Herman Hertzberger as the starting point of every re-design process. Based on this, the primary position in this project toward re-designing Centraal Beheer Office is ‘keeping the rule while breaking the rule’; more precisely, modifying the existing situations while reusing the underlying principle of the building. In other words, instead of conservation nor mere transformation, the project is aiming to become ‘the reinterpretation’ of Centraal Beheer Office. Based on the study of Hertzberger’s architectural idea and Centraal Beheer Office, I set my architectural themes as ‘in-between space, interaction, and coexistence.’ Along with this themes, I set my research question as 'How to make Centraal Beheer Office create interaction through in-between space?' With the new program, Art Academy, the project aimed to 1. how to retrieve the publicness of Centraal Beheer Office, 2. how to accommodate the new program, and 3. how to improve the comfort of the building while keeping the existing value of the building. With this purpose, I connected the building with the city through the urban axis and broaden the inner street to attract the people to come. As follow step, I reorganized the spatial system of the building to apply the new program, Art Academy, to the building. At the last phase, I used a double façade scheme on the building not only for the building comfort but also for creating in-between space between in an outside world.