Service-based architecture have now become commonplace, creating the need to address their systematic maintenance and evolution. We propose a layered pattern-based transformation framework to support a stepwise and incremental Service-Oriented Architecture (SOA) evolution. The framework enables higher-level abstract and system-level operational transformation of SOA elements to facilitate architectural evolution. Higher-level transformations are defined by combining the basic transformation operators and transformation patterns. An abstraction layer encapsulates these primitive transformations into declarative user-defined transformation rules. SOA-specific architectural styles are applied to refine the transformed design to complete a style-based SOA evolution. An electronic payment system case study is used to demonstrate the architectural evolution at different abstraction levels.