Use the following script in the run script activity of the current workflow

answer = true;
var sag = new GlideRecord(‘sysapproval_group’);
sag.addQuery(‘parent’, current.sys_id);
sag.query();
while(sag.next()) {
if(sag.approval == ‘rejected’) {
current.state = ‘4’;

var w = new Workflow();
var gr = new GlideRecord(‘wf_context’);

if (gr.get(current.context))
w.cancelContext(gr);
}
}