In article Save variant for single selection screen subscreen I've shown you how to save a variant for single selection-screen subscreen with a little help of FM RS_ISOLATE_1_SELSCREEN & RS_CREATE_VARIANT. ...
... to firstly use FM 'RS_REFRESH_FROM_SELECTOPTIONS' to get all fields and values for all select-options, then you need to use FM 'RS_ISOLATE_1_SELSCREEN' to get the fieldnames for selected ...