When a guardian appointed or declared by the Cowl is discharged, or, under the law to which the ward is subject, ceases to be entitled to act, or when any such guardian or a guardian appointed by will or other instrument is removed or dies, the Court, of its own motion or on application under Chapter II, may, if the ward is still a minor, appoint or declare another guardian of his person or property, or both, as the case may be.