How to run cron dynamically?

Question

MongoDB

I'm implementing dynamic cron launch. How to stop the old cron before starting the new one?

function test() {
    db.test.findOne({id: 1},)
        .then(res => {
        if (!res)
            return Promise.reject('Period backup not found');
       let job = cron.schedule(res.cronTime, function () {
    
            test1();
        });
            console.log(job)
    })
}
cron.schedule('* * * * *', () => 
    test();
    return true;
});