First articulated by Arnold van Gennep is the idea that there are specific rituals that mark an individual's transition from one social status to another. He called these rituals:

rites of passage

Explanation:

rites of passage is known to be a religious rituals.

It is the beginning of a vital or important changes in individual status or social position at different points in the life cycle, such as birth, marriage or death.

The rites of passage theory by Arnold Van Gennep involves separation, liminality and reintegration.

an informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.