All of the following are requirements for successfully changing organizational culture except:

A) understanding the old culture
B) living the new culture
C) using the most effective subculture in the organization as an example
D) attacking culture head-on

Attacking culture head-on is not a requirement for successfully changing organizational culture. In fact, a direct attack on culture may cause resistance and hinder the change process. Instead, a more effective approach is to gradually introduce new values, behaviors, and practices, and reinforce them through actions and communication. Understanding the old culture, living the new culture, and using the most effective subculture in the organization as an example are important requirements for successful culture change.