Drops a linked server login.
sp_droplinkedsrvlogin [ @rmtsrvname= ] 'rmtsrvname' , [ @locallogin= ] 'locallogin' GO --returns 0=ok 1=failed
Drop the login mapping for an existing user
EXEC sp_droplinkedsrvlogin 'AcctsSEA', 'ericm' GO
Drop the default login mapping
EXEC sp_droplinkedsrvlogin 'AcctsSEA', NULL GO
