vba change named range address
Dim wb As Workbook
Dim nr As Name
Set wb = ActiveWorkbook
Set nr = wb.Names.Item("myRange")
' give an absolute reference:
nr.RefersTo = "=Sheet1!$C$1:$C$9"
' or, resize relative to old reference:
With nr
.RefersTo = .RefersToRange.Resize(100, 1)
End With