If you decide to deactivate synchronization, the model and its source code remain as they were after the last synchronization.
You can deactivate synchronization:
In the Model Explorer, by right-clicking the model and selecting Synchronize, unselecting Synchronized, and clicking Finish.
In the Navigator, by right-clicking the model and selecting Properties, unselecting Synchronized in the PowerDesigner page, and clicking OK.
In the Navigator, right-clicking a synchronized package and selecting Unsynchronize.