Md. Code, Election Law § 5–503

(a) Except as provided in subsection (b) of this section, the certificate of withdrawal shall be filed with the appropriate board with which the individual filed the certificate of candidacy.

(b) The proclamation issued by the Governor under § 8-710 of this article for a special election to fill a vacancy for Representative in Congress shall allow any individual who has filed a certificate of candidacy to withdraw the candidacy as provided under the terms of the proclamation.