Sub FindReplaceAllFilesInFolder()
Application.ScreenUpdating = False
Dim strFolder As String, strFile As String, strDocNm As String, wdDoc As Document
strDocNm = ActiveDocument.FullName: strFolder = GetFolder
If strFolder = "" Then Exit Sub
strFile = Dir(strFolder & "\*.docx", vbNormal)
While strFile <> ""
  If strFolder & "\" & strFile <> strDocNm Then
    Set wdDoc = Documents.Open(FileName:=strFolder & "\" & strFile, AddToRecentFiles:=False, Visible:=False)
    With wdDoc
      Call FnR(.Range)
      .Close SaveChanges:=True
    End With
  End If
  strFile = Dir()
Wend
Set wdDoc = Nothing
Application.ScreenUpdating = True
End Sub
 
Function GetFolder() As String
Dim oFolder As Object
GetFolder = ""
Set oFolder = CreateObject("Shell.Application").BrowseForFolder(0, "Choose a folder", 0)
If (Not oFolder Is Nothing) Then GetFolder = oFolder.Items.Item.Path
Set oFolder = Nothing
End Function

Sub FnR(Rng As Range)
Dim strFindText As String, strReplaceText As String, nSplitItem  As Long
strFindText = "northenn,westenn"
strReplaceText = "northern,western"
With Rng.Find
  .ClearFormatting
  .Replacement.ClearFormatting
  .Forward = True
  .Format = False
  .MatchCase = False
  .MatchWholeWord = False
  .Wrap = wdFindContinue
  For nSplitItem = 0 To UBound(Split(strFindText, ","))
    .Text = Split(strFindText, ",")(nSplitItem)
    .Replacement.Text = Split(strReplaceText, ",")(nSplitItem)
    .Execute Replace:=wdReplaceAll
  Next
End With
End Sub