WPF mvvm passing popup viewmodel value in to main viewmodel

I have a scenario that I have a WPF usercontrol UI, from this UI I will call a pop up usercontrol UI.

When I will select a value from pop up usercontrol UI Grid, then popup ui will be close and the selected popup grid value will get in main UI without visual state change of the main UI. 

Main UI ViewModel:

 private void OnInsplanPicker(object sender)  
     {  
       InsurancePlanLookup window = new InsurancePlanLookup();  
       window.BindEvent += window_BindEvent;  
       DockHelper.AddPanel(window,"Insuranceplan lookup");  
     }  
     void window_BindEvent(long insplanId)  
     {  
       Nhinsplanid_FK = insplanId;  
     }  

Popup code behind

 public partial class InsurancePlanLookup  
   {  
     public delegate void BindDelegate(long insplanId);  
     public event BindDelegate BindEvent;  
     VMInsurancePlanLookup vm ;  
     public InsurancePlanLookup()  
     {  
       InitializeComponent();  
       vm = new VMInsurancePlanLookup();  
       vm.BindEvent += vm_BindEvent;  
       vm.CloseEvent += vm_CloseEvent;  
       DataContext = vm;  
     }  
     void vm_BindEvent(long insplanId)  
     {  
       BindEvent(insplanId);  
       DockHelper.ClosePanel(Parent);  
     }  
     void vm_CloseEvent()  
     {  
       DockHelper.ClosePanel(Parent);  
     }  
   }  

Popup ViewModel

 public delegate void BindDelegate(long insplanId);  
 public event BindDelegate BindEvent;  
 public ICommand Close { set; get; }  
     public ICommand OkButtonCommand { set; get; }  
     public VMInsurancePlanLookup()  
     {  
       Close = new DelegateCommand(OnClose);  
       OkButtonCommand = new DelegateCommand(OnOkButton);  
       PrepareOriginalList();  
     }  
     private void OnOkButton(object obj)  
     {  
       BindEvent(SelectedInsplan.id);  
     }  
     private void OnClose(object obj)  
     {  
       if (CloseEvent != null)  
       {  
         CloseEvent();  
       }  
     }