How to show Panel in MVVM(WPF)?

How to show Panel in MVVM(WPF)?

I made MVVM application using DevExpress and WPF. To show data
NamesView.xaml View will be called in Document Tab Provided by DevExpress.
Code is:
void ShowDocument(Int32? key) {
if(DocumentManagerService == null)
return;
IDocument document = (key != null && key.HasValue) ?
GetDocumentById(key.Value) : null;
if(document == null) {
document = DocumentManagerService.CreateDocument("NamesView", key,
this);
}
document.Show();
}
There is a PanelB in NamesCollectionView.xaml file.How to Show
"NamesView.xaml" in Panel(named as PanelB defined in
NamesCollectionView.xaml file rather than showing in Document Tab?. When
user will Click on Edit or new button, NamesView file will get open in
response.I want that this file to show in PanelB.
Note: I f my Question is not clear or if you need some more code to figure
it out. Please ask me, i will provide you more detail.