Hi Irfan,

You can create a schedule job that Runs as below with script.

executeonLastWeek();

function executeonLastWeek() {
    //gives you current date time
    var getdtime = new GlideDateTime();
	
	//gives you current month number 1-Jan, 2-Feb, so-on
    var getmonth = getdtime.getMonth();
	
	//execute only if it is start of quarter
    if (getmonth == '3' || getmonth == '6' || getmonth == '9' || getmonth == '12') {
		
		//gets you number of days in month 30 or 31 or 29
        var days_in_month = getdtime.getDaysInMonthUTC();
		
		//gets you today's date
        var day_of_month = getdtime.getDayOfMonthUTC();
		
        if (day_of_month >= days_in_month - 6) {
            //return true;
            //your script here to set reminder gs.eventQueue();
        } else {
            //	return false;
            //do nothing
        }
    }
}