Reset ratingcount for list item using javascript

I wish to reset the ratings for an item after a list item is edited. I can get the Average rating to be reset back to 0, but not the ratingCount. How can I do this?

The code I am using is

var context = new SP.ClientContext(_spPageContextInfo.webServerRelativeUrl);
var list = context.get_web().get_lists().getById(_spPageContextInfo.pageListId);

// test case is item 2 in my list

var item = list.getItemById(2);

context.load(item, "RatingCount", "AverageRating");
context.executeQueryAsync(RetrievedListID, ExecutionFailed);

function RetrievedListID(sender, args) {
var rc = item.get_item("RatingCount");
var ar = item.get_item("AverageRating");
item.set_item('AverageRating',0);
item.set_item('RatingCount',0);
item.update();

context.executeQueryAsync(RetrievedListID1, ExecutionFailed1);

function RetrievedListID1(sender, args) {alert('Done')};
function ExecutionFailed1(sender, args) {alert('Failed')};
 }

  function ExecutionFailed(sender, args) {
    alert('Failed');
  }
}