ASEAN is a group of Southeast Asian countries that has grown persistently ever since it was founded in 1967. By 2025 onward, ASEAN objects to expand even more. The vision towards growth and being global, perhaps, relates with 1300 meetings per year that are held in Jakarta headquarter. The office building hasn't changed much since 1982. Departing from that, visioning 50 years ahead is how the question approached. As the organization becomes more global and how people work become more fluid, the conventional office typology will be less needed. Thus, the main feature of the design proposal is adjustable spaces. Office spaces in the building are generally open and flexible for a certain number of purposes. The spaces are filled out with ‘informal’ seating and ‘conventional’ cubicles. That can be used as working spaces, meeting rooms, and, perhaps, lounges too. Moreover, spatial configuration in the building enhances interaction. Spaces and its functions are grouped into modules, and then arranged criss-crossed with another by using height difference. They are split 80cm starting from the 4th floor upward. Furthermore, on the ground floor, a plaza is placed in the center. Providing outdoor gallery and greenery in the plaza is not only to create horizontal connection with the surrounding, but also vertical one. By doing so, the plaza, which is circled by the criss-crossed office spaces, has a center of activities and becomes able to serve as an atrium.