When business requirements change radically, it signifies a need for Business Process Reengineering (BPR) rather than simple incremental improvement. In such scenarios, a thoroughly documented As-Is process model is crucial. It serves as an essential baseline to understand the full scope of the existing problems, identify all impacted areas, justify the need for radical change to stakeholders, and provide a foundation for managing the complex transition to the new To-Be process. Without a clear As-Is model, the risks associated with a radical redesign increase significantly.

A. If a business process is new, there is no "As-Is" process to use as a basis; the design starts directly with the "To-Be" model.

C. New regulatory rules typically require specific, often incremental, changes to an existing process, not necessarily a complete redesign.

D. If a clear definition of the current activities cannot be obtained, it is impossible to create an As-Is model to use as a basis.

Harmon, P. (2014). Business Process Change: A Guide for Business Managers and BPM and Six Sigma Professionals (3rd ed.). Morgan Kaufmann. p. 198. Harmon states, "If an organization is contemplating a radical change, it is still important to create an As-Is process model... The As-Is model provides a baseline for discussing what is wrong with the existing process and for measuring the nature of the proposed change."

Weske, M. (2019). Business Process Management: Concepts, Languages, Architectures (3rd ed.). Springer. pp. 24-26. Discusses the BPM lifecycle, where the As-Is modeling phase is a prerequisite for analysis and redesign, especially in complex transformation projects.