[flexcoders] Killing a Singleton

[Wally Kolcz]

I want when the user logs out, the instance of the Singleton that 
supports their global information to get set to null. How can you delete 
a Singleton existence or set it to null?

package org.mywindow.model
{

     [Bindable]
     public final class UserDataModel {

     private static var instance:UserDataModel;

     public function UserDataModel(singletonEnforcer:MySingletonEnforcer) {
         if (singletonEnforcer == null) {
             throw new Error ("UserDataModel is a singleton class, use 
getInstance() instead");
         }
     }

         public static function getInstance():UserDataModel {
             if (instance == null)
             instance = new UserDataModel(new MySingletonEnforcer());
             return instance;
         }
     }
}

class MySingletonEnforcer {}

Thanks!