Software systems endure many noteworthy changes throughout their life-cycle in order to follow the evolution of the problem domains. Generally, the software system architecture cannot follow the rapid evolution of a problem domain which results in the discrepancies between the implemented and designed architecture. Software architecture illustrates a system's structure and global properties and consequently determines not only how the system should be constructed but also leads its evolution. Architecture plays an important role to ensure that a system satisfies its business and mission goals during implementation and evolution. However, the capabilities of the designed architecture may possibly be lost when the implementation does not conform to the designed architecture. Such a loss of consistency causes the risk of architectural decay. The architectural decay can be avoided if architectural changes are made as early as possible. The paper presents the Process Model for Architecture-Centric Evolution which improves the quality of software systems through maintaining consistency between designed architecture and implementation. It also increases architecture awareness of developers which assists in minimizing the risk of architectural decay. In the proposed approach consistency checks are performed before and after the change implementation.