[Solved]-Changing bar colors on data that is within the same series data-Highcharts

The details for how to do this are clear in the API documentation: http://api.highcharts.com/highcharts#series.data.color, you can set the color on an individual data point, see here:

So, from your example this does what you want:

var chart = new Highcharts.Chart({
    chart: {
        renderTo: 'container',
        type: "bar"
    },
    xAxis: {
        categories: [ "July", "August", "September", "October"]
    },
    series: [{
        data: [2341, 1245, 989, { color: 'red', y: 1829 } ],
    }]
});

Fiddle

If you want to change the colour later then the linked answer in the comments shows how -- there is a loop there changing all the points, you can use it to change just one.