MySQL Table already exists error when altering table to convert int auto incrementing column to bigint

MySQL Table already exists error when altering table to convert int auto
incrementing column to bigint

ERROR 1025: Error on rename of './samedaycrm4/#sql-4f4_1b5' to
'./samedaycrm4/customers' (errno: 150)
SQL Statement:
ALTER TABLE `samedaycrm4`.`customers`
CHANGE COLUMN `idcustomers` `idcustomers` BIGINT NOT NULL AUTO_INCREMENT
ERROR: Error when running failback script. Details follow.
ERROR 1050: Table 'customers' already exists
SQL Statement:
CREATE TABLE `customers` (
`idcustomers` int(11) NOT NULL AUTO_INCREMENT,
`firstname` varchar(45) DEFAULT NULL,
`lastname` varchar(45) DEFAULT NULL,
`address1` varchar(45) DEFAULT NULL,
`address2` varchar(45) DEFAULT NULL,
`city` varchar(45) DEFAULT NULL,
`state` varchar(45) DEFAULT NULL,
`zip` varchar(45) DEFAULT NULL,
`phone` varchar(45) DEFAULT NULL,
`email` varchar(45) DEFAULT NULL,
`cell` varchar(45) DEFAULT NULL,
`company` varchar(45) DEFAULT NULL,
PRIMARY KEY (`idcustomers`),
UNIQUE KEY `idcustomers_UNIQUE` (`idcustomers`)
) ENGINE=InnoDB AUTO_INCREMENT=390 DEFAULT CHARSET=latin1
I wondering if there is a way to alter the auto-incrementing primary int
key to bigint without having to create a new table. I would like to modify
the existing one.
Thanks in advance...