You drop a remote server with the sp_dropserver system procedure, which deletes the entry for that server from the sysservers table. When you drop a remote server, a user can no longer access its information through the local server.
sp_dropserver server_name [, droplogins]
where
The droplogins option is not needed to drop the local server's entry, because the local server does not have remote login information associated with it.
For example, to drop EXPENSES and its remote logins, type:
sp_dropserver expenses, droplogins
For more information about sp_dropserver, see the Microsoft SQL Server Transact-SQL Reference.