if I have an assembly in Solidworks with its reference parts. but I want to make the same assembly with another dimension that is different from the parent assembly what needs to be done I need to make a new assembly or any chance to use the same assembly with modification please guide me
Have you looked at SW configurations ? Otherwise if you "Save as" assembly it will keep all the references to subcomponents, if your goal is to make a copy of every thing including subcomponents you can use "pack and go"