Sql-server – Sql Server Replication requires the actual server name to make a connection to the server

You need to check both sys.remote_logins and sys.linked_logins. You should be able to build a script dynamically to drop the set you find:

DECLARE @sql NVARCHAR(MAX) = N'';

SELECT @sql += N'EXEC sys.sp_droplinkedsrvlogin @s, N''' + remote_name + N''''
  FROM sys.linked_logins
  WHERE server_id = 0 AND remote_name IS NOT NULL;

SELECT @sql += N'EXEC sys.sp_dropremotelogin @s, N''' + remote_name + N''''
  FROM sys.remote_logins
  WHERE server_id = 0 AND remote_name IS NOT NULL;

PRINT @sql; -- spot check will only show first 8K of command

DECLARE @s NVARCHAR(512) = N'old server name';
--EXEC sys.sp_executesql @sql, N'@s NVARCHAR(512)', N'.\SQL2014';

"abc" would be a default instance, where "abc" is the actual server name. Sounds like you created a named instance where /xyz is the name of the instance. This allows you to have multiple instances of SQL Server on the same server. The only way to remove the instance is to uninstall SQL Server and then reinstall with the name you want.