D.C. Code § 16-3109
The Probate Court may order a personal representative, special administrator, guardian, or testamentary trustee, who appears to be in default in respect to the rendering of an inventory or account or the fulfillment of a duty in the court, to be summoned to appear therein and fulfill his duty in the premises, on pain of revocation of his power to act. On his appearance, the court may make such order as is just. On his failure to appear, after having been duly summoned, the court may revoke his power to act and make such further order and other appointment as justice requires. If the summons to appear is returned by the marshal "not to be found," an alias summons shall be mailed to the last-known post-office address of the fiduciary or served upon his attorney of record, if he is within the jurisdiction of the court. On the failure of the fiduciary to appear, the court may revoke his power to act and make such further order and other appointment as justice requires.
D.C. Code § 16-3109