Microservices architecture offers a high scalability and maintainability rate than monolithic architecture, making them an interesting option for software modernization. This architectural style enables the implementation of loosely coupled services. A modernization for monolithic architecture to microservice may require the methods as well as techniques that are used for the decomposition into services and well operations of the new architecture. However, In operation the complexity that follows the functionality redesign is still observed. In this paper, we extend the DDD (Domain Driven Design) decomposition of microservice with the consideration of the principles of microservice as the way of transformation of the legacy system. This includes finding the right boundary of microservice and defining working organization criteria for microservice architecture. Specifically, using the proposed modernization process will help an organization to plan and perform modernization. This leads to microservice architecture for increasing scalability, maintainability and enabling automated infrastructure orchestration. This research demonstrate the use of systematic framework in a case study.