Change RefersTo of an already existing range name

Hi,

What is the code to change the RefersTo portion of a range name?

I'm trying this but it's not working:

ActiveWorkbook.Names("Database_User_SheetSelected_EntireRange").RefersTo = "='" & Sheet15.Range("Database_User_SheetSelected_ActiveDatabase") & "'!$1:$65500"

The RefersTo portion works when I want to ADD that range name, but fails when I want to simply change the range reference.

Thanks,

Lawrence