Hi @mallikabhupathiraju 

Please follow the steps below to achieve your requirement:

BR:

Table : Catalog Task

After Update

Condition of BR: State Changes;

Script:

(function executeRule(current, previous /*null when async*/) {

	// Add your code here
	if(current.state.changes()){
		updateRITMState(current.request_item,current.state);
	}
	
	function updateRITMState(RitmID,state){
		var gr = new GlideRecord('sc_req_item');
		gr.addQuery('sys_id',RitmID);
		gr.query();
		if(gr.next()){
			gr.state = state;
			gr.update();
		}
	}
	

})(current, previous);

Hope this helps. Please mark the answer as correct/helpful based on impact.

Regards,
Shloke