Use VBA to change colors of slide elements in Powerpoint 2013

This should get you a step closer, though I'd probably rewrite it as a function that you could pass lFindColor and lReplaceColor to.

Sub ReplaceColors()

    Dim lFindColor As Long
    Dim lReplaceColor As Long
    Dim oSl As Slide
    Dim oSh As Shape
    Dim x As Long

    lFindColor = RGB(255, 128, 128)
    lReplaceColor = RGB(128, 128, 255)

    For Each oSl In ActivePresentation.Slides
        For Each oSh In oSl.Shapes
            With oSh

                ' Fill
                If .Fill.ForeColor.RGB = lFindColor Then
                    .Fill.ForeColor.RGB = lReplaceColor
                End If

                ' Line
                If .Line.Visible Then
                    If .Line.ForeColor.RGB = lFindColor Then
                        .Line.ForeColor.RGB = lReplaceColor
                    End If
                End If

                ' Text
                If .HasTextFrame Then
                    If .TextFrame.HasText Then
                        For x = 1 To .TextFrame.TextRange.Runs.Count
                            If .TextFrame.TextRange.Runs(x).Font.Color.RGB = lFindColor Then
                                .TextFrame.TextRange.Runs(x).Font.Color.RGB = lReplaceColor
                            End If
                        Next
                    End If
                End If
            End With
        Next
    Next

End Sub