Sub PartialWorkbookName()

  Const cStrPartial As String = "Website_20"

  Dim wb As Workbook
  Dim objWb As Workbook

  For Each wb In Workbooks
    If Left(wb.Name, Len(cStrPartial)) = cStrPartial Then
      Set objWb = Workbooks(wb.Name)
      Exit For
    End If
  Next
  If objWb Is Nothing Then GoTo NotFound

  With objWb
    ' Code in here


  End With

  Set objWb = Nothing

Exit Sub
NotFound:
  MsgBox "Workbook not found."
End Sub