Maryland Code, Election Law § 5-1002

(b)(1)(i) A vacancy in nomination that occurs because a nominee declines the nomination shall be filled by the State central committee of the political party to which the nominee belongs by the 88th day before the general election.

(ii) A vacancy in nomination that occurs because a nominee dies or is disqualified for any cause shall be filled by the State central committee of the political party to which the nominee belongs by the 81st day before the general election.

(2)(i) The State central committee shall file a certificate of designation for the nominee with the State Board.

(ii) The successor nominee designated by the State central committee under subparagraph (i) of this paragraph shall file a certificate of candidacy with the State Board.