Yes, you may move or change one of the service in your bundled service (such as Maxis Unlimited Postpaid & Fibre and Family Plan) to another account or change to a rate plan not offered by the bundled; you will required to split the services first prior to your intended change.
Important note:-
To check if you have any contract for the bundled service.
You will stop enjoying any benefits which come with the bundled service such as unlimited data and etc.