Use this macro:
Private Sub EditNames()
Dim Name As Name
Dim TempRange As Range
Dim RangeName As String
For Each Name In ThisWorkbook.Names
If Left(Name.Name, 2) = "XX" Then
RangeName = "FNX" & Mid(Name.Name, 3)
Set TempRange = Name.RefersToRange
Name.Delete
TempRange.Name = RangeName
End If
Next Name
End Sub
Kevin