See below
Use the below code, If you are using excel 2007 or 2010 and want to reorder the legends only. Make sure mChartName matched with your chart name.
Sub ReverseOrderLegends()
mChartName = "Chart 1"
Dim sSeriesCollection As SeriesCollection
Dim mSeries As Series
With ActiveSheet
.ChartObjects(mChartName).Chart.SetElement (msoElementLegendNone)
.ChartObjects(mChartName).Chart.SetElement (msoElementLegendRight)
Set sSeriesCollection = .ChartObjects(mChartName).Chart.SeriesCollection
For Each mSeries In sSeriesCollection
If mSeries.Values(1) = 0.000000123 Or mSeries.Values(1) = Empty Then
mSeries.Delete
End If
Next mSeries
LegendCount = .ChartObjects(mChartName).Chart.SeriesCollection.Count
For mLegend = 1 To LegendCount
.ChartObjects(mChartName).Chart.SeriesCollection.NewSeries
.ChartObjects(mChartName).Chart.SeriesCollection(LegendCount + mLegend).Name = .ChartObjects(mChartName).Chart.SeriesCollection(LegendCount - mLegend + 1).Name
.ChartObjects(mChartName).Chart.SeriesCollection(LegendCount + mLegend).Values = "={0.000000123}"
.ChartObjects(mChartName).Chart.SeriesCollection(LegendCount + mLegend).Format.Fill.ForeColor.RGB = .ChartObjects(mChartName).Chart.SeriesCollection(LegendCount - mLegend + 1).Format.Fill.ForeColor.RGB
Next mLegend
For mLegend = 1 To LegendCount
.ChartObjects(mChartName).Chart.Legend.LegendEntries(1).Delete
Next mLegend
End With
End Sub