Online Partition addition use "add partition" clause or "reorganize" clause?

[Tom Song]

MySQL version is 5.6.13

This is table script:

CREATE TABLE `user_calllog` (
`FID` int(11) NOT NULL AUTO_INCREMENT,
`FCALLCATEGORY` varchar(32) DEFAULT NULL,
`FCREATEBY` varchar(36) DEFAULT NULL,
`FDATECREATED` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`FDATELASTUPDATE` datetime DEFAULT NULL,
`FCALLTYPE` varchar(32) DEFAULT NULL,
`FSTATUS` char(1) DEFAULT NULL,
`FTITLE` varchar(32) DEFAULT NULL,
`FATTACHEDFILE` varchar(64) DEFAULT NULL,
`FDESC` varchar(1000) DEFAULT NULL,
`FUSERID` varchar(255) DEFAULT NULL,
`FWEBCODE` varchar(7) DEFAULT '',
PRIMARY KEY (`FID`,`FDATECREATED`),
KEY `i_user_calllog_fuserid` (`FUSERID`),
KEY `idx_user_calllog_fdatecreated` (`FDATECREATED`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
PARTITION BY RANGE COLUMNS (FDATECREATED)
(
PARTITION p_201406 VALUES LESS THAN ('2014-07-01'),
PARTITION p_201407 VALUES LESS THAN ('2014-08-01'),
PARTITION p_201408 VALUES LESS THAN ('2014-09-01'),
PARTITION p_201409 VALUES LESS THAN ('2014-10-01'),
PARTITION p_201410 VALUES LESS THAN ('2014-11-01'),
PARTITION p_201411 VALUES LESS THAN ('2014-12-01'),
PARTITION p_MAX VALUES LESS THAN (MAXVALUE)
);

2 choices:

1. "add partition" clause

--Can confirm that p_MAX partition no record

ALTER TABLE user_calllog DROP PARTITION p_MAX;
alter table user_calllog add PARTITION (partition p_201412 VALUES LESS THAN ('2015-01-01'));

2. "reorganize" clause
ALTER TABLE user_calllog REORGANIZE PARTITION p_MAX INTO (
PARTITION p_201412 VALUES LESS THAN ('2015-01-01'),
PARTITION p_MAX VALUES LESS THAN (MAXVALUE)
);

Please help advise which one is ok for online ddl operation, or both ok? thanks