Change checkbox icon of "Ext.selection.CheckboxModel" in ExtJS 5

I want to change checkbox icon of "Ext.selection.CheckboxModel" on button click in ExtJs5. I am using CheckBoxModel in grid.

When checkbox render or display first time, then i am able to change its icon based on condition but i want to change icon on button click or can say dynamically.

Ex. Below is the syntax of using CheckBoxModel in my grid. It's working properly.

    {
    xtype: 'grid',
    selModel: Ext.create('Ext.selection.CheckboxModel',
   {
   renderer: function (value, metaData, record, rowIndex, colIndex, store, view) {
   if (record.data.hold) {
      return '';
    } else {
    return '<div class="x-grid-row-checker">&nbsp;</div>';
    }
   }});
   }
   {
      xtype: 'button',
      handler: function(){
      //When button will be clicked, icon should be change of checkbox.
      }
   }