How to take control of the securities contained in minor account?

The minor account is linked with the custodian account that is under the minor parent's or guardian's primary account. Security registered in the minor's account with the name of SSN of the minor in the format of either with sole owner, or primary owner with beneficiary or primary with secondary owner etc. So minor directly can't permit purchase securities. The custodian must conduct all the transactions behalf of minor and the custodian can purchase securities behalf of the minor.