Comunicating Between ViewModels

Question

Hello. 

 

I have a main ViewModel that loads two seperate child viewmodels. like so:

 

/// <summary>
       /// Used to load edit/list user ViewModels.
       /// </summary>
       public MVVM.ViewModelBase ViewModel
       {
           get { return viewModel; }
           set
           {
               viewModel = value;
               RaisePropertyChanged("ViewModel");
           }
       }
       MVVM.ViewModelBase viewModel;

       public UsersViewModel()
       {
           this.ViewModel = new UsersListViewModel();
       }

       /// <summary>
       /// Adds a new user
       /// </summary>
       void addUserExecute()
       {
           ViewModel = new UsersEditViewModel(-1);
       }
       bool canAddUserExecute()
       {
           return true;
       }
       public ICommand AddUser { get { return new MVVM.RelayCommand(addUserExecute, canAddUserExecute); } }

 I can't seem to figure out how to let my child (UsersEditViewModel) to tell the parent that i'm done editing and need to close/dispose.

 

Any help would be greatly appreciated.