# Pastebin 5Dn7SMAj
mysql> create table t (nonenum varchar(255), anenum ENUM('x', 'y'));
Query OK, 0 rows affected (0.07 sec)

mysql> insert into t (nonenum, anenum) values ('Thing', 'x');
Query OK, 1 row affected (0.04 sec)

mysql> insert into t (nonenum, anenum) values ('Thing', 'x');
Query OK, 1 row affected (0.00 sec)

mysql> insert into t (nonenum, anenum) values ('Thing', 'y');
Query OK, 1 row affected (0.01 sec)

mysql> insert into t (nonenum, anenum) values ('Thing', 'y');
Query OK, 1 row affected (0.00 sec)

mysql> select * from t;
+---------+--------+
| nonenum | anenum |
+---------+--------+
| Thing   | x      |
| Thing   | x      |
| Thing   | y      |
| Thing   | y      |
+---------+--------+
4 rows in set (0.00 sec)

mysql> show create table t
    -> ;
+-------+----------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                           |
+-------+----------------------------------------------------------------------------------------------------------------------------------------+
| t     | CREATE TABLE `t` (
  `nonenum` varchar(255) DEFAULT NULL,
  `anenum` enum('x','y') DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+----------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> alter table t modify anenum varchar(255);
Query OK, 4 rows affected (0.15 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> select * from t
    -> ;
+---------+--------+
| nonenum | anenum |
+---------+--------+
| Thing   | x      |
| Thing   | x      |
| Thing   | y      |
| Thing   | y      |
+---------+--------+
4 rows in set (0.00 sec)

mysql> show create table t;
+-------+---------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                          |
+-------+---------------------------------------------------------------------------------------------------------------------------------------+
| t     | CREATE TABLE `t` (
  `nonenum` varchar(255) DEFAULT NULL,
  `anenum` varchar(255) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+---------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql>