Since it's not a GSM phone it can't be locked to a specific carrier's SIM card (since it doesn't use a SIM card) so that would be like plucking the feathers off an elephant. You can't unlock something that can't be locked.
CDMA phones are "locked" in a different way - the carrier has the serial numbers of all the phones it will allow on its network. If yours is for a different carrier, the carrier you want to go to won't have that phone in the database, so it won't work.