SolidWorks STEP Edit & DXF Output

I need you to open an existing STEP model in SolidWorks, make a round of feature-level edits—specifically adding or removing geometry I will mark up—and then export a clean, ready-to-prototype DXF. No wholesale dimension changes or full redesigns are required; the core shape stays intact, only select features come or go.

When the modifications are complete I expect:
• the updated, fully parametric SolidWorks file
• the corresponding STEP for reference
• a flat DXF that a prototyping shop can use without extra cleanup

Accuracy matters because this file heads straight to a rapid-prototyping vendor. Keep the feature tree organized and name any new sketches so the model remains easy to update later. Let me know your SolidWorks version before starting so we avoid compatibility surprises.