This example searches for a navigation node with the label "Sale", and then updates it.
Private Sub ChangeNavLabel()
Dim myFiles As WebFiles
Dim myFile As WebFile
Set myFiles = ActiveWeb.RootFolder.Files
For Each myFile in myFiles
If myFile.NavigationNode.Home.Label = "Sale" Then
myFile.NavigationNode.Home.Label = "Sales Items"
End If
Next
End Sub