Md. Code, Elec. Law § 3-502

(a) (1) In this section the following words have the meanings indicated. (2) “Confirmation notice” means a notice, approved by the State Board, that is sent by forwardable mail with a return card. (3) “Return card” means a postage prepaid and preaddressed card on which the voter may report the voter’s current address. (b) Upon receiving any information that a voter currently registered in the State has moved to a different address within the State, the appropriate election official shall change the voter’s record and send the voter a confirmation notice. (c) If it appears from information provided by the postal service or an agency specified in § 3-504(b) of this subtitle that a voter has moved to a different address outside the State, the election official in the county where the voter most recently resided in the State shall send the voter a confirmation notice informing the voter of his or her potential inactive status as described in § 3-503 of this subtitle. (d) Upon receipt of a return card, the election director shall: (1) make any needed corrections in the statewide voter registration list; and (2) in accordance with State Board guidelines, retain original voter registration documents. (e) The election director may not remove a voter from the statewide voter registration list on the grounds of a change of address unless: (1) the voter confirms in writing that the voter has changed residence to a location outside the State; or (2) (i) the voter has failed to respond to a confirmation notice under subsection (c) of this section; and (ii) the voter has not voted or appeared to vote (and, if necessary, corrected the record of the voter’s address) in an election during the period beginning with the date of the notice through the next two general elections.