Option Explicit
'Graham Mayor - https://www.gmayor.com - Last updated - 23 Nov 2021

 
Sub ReplaceInStoryRanges()
Const sPath As String = "C:\Path\docname.docx" ' the path of the document
Dim WordDoc As Object
Dim wdApp As Object
Dim oStory As Object
Dim oShp As Object
Dim bFormat As Boolean

    On Error Resume Next
    Set wdApp = GetObject(, "Word.Application")
    If Err Then
        Set wdApp = CreateObject("Word.Application")
    End If
    On Error GoTo 0
    Set WordDoc = wdApp.Documents.Open(sPath) 'works in Word even if the document is already open
    
    'record autoformat option
    bFormat = wdApp.Options.AutoFormatAsYouTypeReplaceQuotes
    'set autoformat option to off
    wdApp.Options.AutoFormatAsYouTypeReplaceQuotes = False
    'process each storyrange by enumeration
    For Each oStory In WordDoc.StoryRanges
        Select Case oStory.StoryType
            Case 1 To 11 'the principle storyranges
            'see https://apireference.aspose.com/words/net/aspose.words/storytype)
                Do
                    ReplaceQuotes wdApp, WordDoc, oStory 'run the external sub
                    DoEvents
                    On Error GoTo 0
                    Select Case oStory.StoryType
                        Case 6, 7, 8, 9, 10, 11 'header/footer ranges
                            'process text boxes etc in the header/footer ranges separately
                            If oStory.ShapeRange.Count > 0 Then
                                For Each oShp In oStory.ShapeRange
                                    If oShp.TextFrame.HasText Then
                                        ReplaceQuotes wdApp, WordDoc, oStory 'run the external sub
                                    End If
                                    DoEvents
                                Next oShp
                            End If
                        Case Else
                    End Select
                    On Error GoTo 0
                    Set oStory = oStory.NextStoryRange
                Loop Until oStory Is Nothing
            Case Else
        End Select
        DoEvents
    Next oStory
    'restore original autoformat option
    wdApp.Options.AutoFormatAsYouTypeReplaceQuotes = bFormat
End Sub

Sub ReplaceQuotes(wdApp As Object, oDoc As Object, oRng As Object)
Dim oFind As Object
Dim vFindText As Variant
Dim vReplText As Variant
Dim bQuotes As String
Dim i As Long
    vFindText = Array(Chr(147), Chr(148), Chr(145), Chr(146))
    vReplText = Array(Chr(34), Chr(34), Chr(39), Chr(39))
    For i = LBound(vFindText) To UBound(vFindText)
        Set oFind = oRng.Duplicate
        With oFind.Find
            Do While .Execute(vFindText(i))
                oFind.Text = vReplText(i)
                oFind.Collapse 0
            Loop
        End With
    Next i
lbl_Exit:
    Set oFind = Nothing
    Exit Sub
End Sub