Models cannot have an active independent account and a studio one at the same time (or two accounts under different studios at the same time).
If you want your account under the studio to be deleted, you should contact them directly and request to delete the account you have with them.
Studios can also detach your model account from them, however, only the studio can decide to do that. Check more information about detaching your account from a Studio here.
Please note, if you already have an active model account when creating a new one, your previous account will be rejected automatically once a new account is verified.