I think that the best way to get a visual on this mass replacement is to open the ICT window and select the Symbol Properties tab. Go to the Part Number column or one of the other columns and sort the parts. Scroll down the and select the rows that contain the parts that you wish to replace. This will select the part in any schematic sheet. Now move the cursor over any one of the selected parts on any of the schematic pages and right mouse button click to open the action menu. Select Replace Symbol/Part to bring up the replacement window. Now go to the DxDatabook or Place Part window and select a replacement part. Check the Preserve "Ref Designator" box and the All open sheets button. Click on the Replace button. Check some of the part's properties to make sure that the parts have been replaced. ICT window, Properties window or schematic page window will all do for checking.