Md. Code, Land Use § 10–406

(a) If five members of the Board are present, the concurring vote of at least four members is necessary to:

(1) reverse any order, requirement, or decision of an administrative officer or unit;

(2) decide in favor of the applicant on any matter on which the Board is required to act under a local law; or

(3) effect any variation in a local law.

(b) If four members of the Board are present, the concurring vote of at least three members is necessary to take any action under this section.