Maryland Code, Health-General § 5-623

(b)(1) The registrant shall notify the electronic advance directives service recognized by the Maryland Health Care Commission if the registrant has amended or revoked a registered advance directive.

(2) A health care provider that becomes aware that a registrant has amended or revoked a registered advance directive shall, at the request of the registrant, provide the registrant with information on how to notify the electronic advance directives service recognized by the Maryland Health Care Commission.

(c)(1) Except as provided in paragraph (2) of this subsection, an individual is not required to submit an advance directive to an electronic advance directives service recognized by the Maryland Health Care Commission.

(2) An individual shall submit an electronic advance directive that is not witnessed to an electronic advance directives service that is recognized by the Maryland Health Care Commission.