Suhas Patil,
You can use labelFormatter function on axisY to convert the axisY labels to percentages.
To switch the axisY labels from percentages to absolute values you can create a drop-down menu with the respective options. Based on the option selected you can update the labelFormatter function and then call chart.render().
document.getElementById("changeAxisYLabel").addEventListener('change', function(event){
if (event.target.value == "absoluteValue") {
chart.options.axisY.labelFormatter = function(e) {
return e.value;
}
}
else if (event.target.value == "percentage") {
chart.options.axisY.labelFormatter = convertToPercentage;
}
chart.render();
});
Please take a look at this JSFiddle for a working example on the same.

—
Thangaraj Raman
Team CanvasJS