We have recently finished Migrating to Lightning. In lightning on case related list there is not an option to copy parent detail.  We currently have users cloning and keying or selecting the parent case field as a work around.  However, people forget or select the wrong case for parent case.  What would be the steps to duplicate the function of copying parent detail on a case.  I have done it in process builder, but need to be able to do it in a button on the case using a button or a button on related list.