how to change service options in controller in angularjs

I'm working on an ionic app, I have written an angularjs service for ionic confirm popup,

service

   app.factory("PopupSer", ["$rootScope", "$ionicPopup",
      function ($rootScope, $ionicPopup) {
         return {
            delete: function () {

               $rootScope.popup = $ionicPopup.confirm({
                  title: 'Delete Title', 
                  cssClass: '',
                  subTitle: '',
                  template: '',
                  templateUrl: '',
                  cancelText: 'No',
                  cancelType: '',
                  okText: 'Yes',
                  okType: 'button-balanced'
               });
            }, // delete

            hide: function () {
               $rootScope.popup.hide();
            }

         }; // return
      }
   ]);

Now, I want to change (for example) confirm title, cancelText or okText in my controller, something like this:

controller

PopupSer.delete({
    title: 'Are You Sure About That?'
});

How can I do this when I call service in my controller?

Extend a "default options" object (doc):

app.factory("PopupSer", ["$rootScope", "$ionicPopup",
  function ($rootScope, $ionicPopup) {
     return {
        delete: function (options) {
           var default_options = {
              title: 'Delete Title', 
              cssClass: '',
              subTitle: '',
              template: '',
              templateUrl: '',
              cancelText: 'No',
              cancelType: '',
              okText: 'Yes',
              okType: 'button-balanced'
           };
           $rootScope.popup = $ionicPopup.confirm(angular.extend(default_options, options));
        }, // delete

        hide: function () {
           $rootScope.popup.hide();
        }

     }; // return
  }
]);