Private Sub DoColorChange(SearchColor As Long, ReplaceColor As Long)
Dim oDoc As Document
Dim oRng As Range
Set oDoc = ActiveDocument
Set oRng = oDoc.Range
With oRng.Find
    .Highlight = True
    .Wrap = wdFindStop
    Do While oRng.Find.Execute
        If oRng.HighlightColorIndex = SearchColor Then
           oRng.HighlightColorIndex = ReplaceColor
        End If
        oRng.Collapse wdCollapseEnd
        If oRng.End = ActiveDocument.Range.End - 1 Then Exit Do
    Loop
End With
End Sub