Public Sub X()

    Dim rng As Range
    Dim varValue As Variant
    Dim varTemp As Variant
    Dim avarItems As Variant
    Dim intI As Integer
    
    With ActiveDocument
        Set rng = .Range( _
          Start:=.Paragraphs( 1 ).Range.Start, _
          End:=.Paragraphs(.Paragraphs.Count).Range.End)
    End With
    
    varValue = rng.Text
    
    avarItems = Split(varValue, Chr( 13 ))
    
    For intI = LBound(avarItems) To UBound(avarItems) -  1 
        If InStr(avarItems(intI), "   ") =  1  Then
            If Not IsEmpty(varTemp) Then
                varTemp = varTemp & Chr( 13 ) & avarItems(intI)
            Else
                varTemp = avarItems(intI)
            End If
        Else
            varTemp = varTemp & " " & avarItems(intI)
        End If
    Next
    
    rng.Text = varTemp
End Sub

Sub X2()

    Dim p As Paragraph
    
    For Each p In ActiveDocument.Paragraphs
        If InStr(p.Range.Text, "   ") <>  1  Then
            p.Previous.Range = _
              Replace(p.Previous.Range, Chr( 13 ), " ")
        End If
    Next p
End Sub