I renamed SQL instance
exec sp_dropserver 'oldname' go excec add_linkedserver 'newname'
select @@servername shows new server, but,
exec sp_helpserver shows old and instance names.
In the registry, i updated name under SQL server keys but it didn't change anything
As soon as i run
sp_dropserver 'oldname', 'droplogins'
it shows only new name but if i run sp_helpserver again, old one appears too in second row