Syntax:
DROP SERVER [ IF EXISTS ] server_name

Drops the server definition for the server named server_name. The
corresponding row in the mysql.servers table is deleted. This statement
requires the SUPER privilege.

Dropping a server for a table does not affect any FEDERATED tables that
used this connection information when they were created. See [HELP
CREATE SERVER].

URL: http://dev.mysql.com/doc/refman/5.6/en/drop-server.html

