Direct3D applies general antialiasing whenever each polygon or line is rendered — no separate pass is required.
On some hardware, general antialiasing can be applied only when the application has rendered the polygons sorted from back to front. To find out whether this is true of the current hardware, you can check the D3DPRASTERCAPS_ANTIALIASSORTDEPENDENT flag (which means that the application must sort the polygons) and the D3DPRASTERCAPS_ANTIALIASSORTINDEPENDENT flag (which means that the application need not sort the polygons). These flags are part of the dwRasterCaps member of the D3DPRIMCAPS structure.
After finding out whether or not you need to sort the polygons, set the render state D3DRENDERSTATE_ANTIALIAS to D3DANTIALIAS_SORTDEPENDENT or D3DANTIALIAS_SORTINDEPENDENT and draw the scene.
When you no longer need general antialiasing, disable it by setting D3DRENDERSTATE_ANTIALIAS to D3DANTIALIAS_NONE.