Keyboard shortcut: Ctrl + Shift + Alt + R
Replace all selected objects with the active object. The "Single User" option will make duplicated objects unique or instances, so they can be modified all at once.
Steps to follow:
1. Select the objects that can be replaced.
2. Mark the active object to be the one that replaces the selected objects.
3. Check or uncheck the "Single User" option depending on whether you want unique objects or instances.
4. When you press the "Replace Obj Act" button, the selected objects will be replaced by the active object.
