Maryland Election Law Section 3-303

      (a)      Except as provided in subsections (b) and (c) of this section, a local board, at the signed request of a registered voter, shall change that voter's party affiliation, or change the voter to or from a decline, at any time that registration is open.

      (b)      (1)      Except as provided in paragraph (2) of this subsection, party affiliation may not be changed:

                  (i)      from 9 p.m. on the Monday, or the next regular business day if the Monday is a legal holiday, that is 12 weeks before the day on which a primary election is to be held under § 8-201 of this article, until and including the day on which the registration reopens after the primary election is held; and

                  (ii)      from and including the day of issuance of a gubernatorial proclamation calling a special election, pursuant to § 8-710 of this article, or from 5 p.m. on the next regular business day if the day of issuance is a legal holiday, until and including the day on which that special election is held.

            (2)      If a voter requests a party affiliation change during a period specified in paragraph (1) of this subsection, the local board shall make the change if:

                  (i)      there is sufficient evidence, as determined by the local boards pursuant to regulations adopted by the State Board, that the request was mailed before the beginning of the period specified in paragraph (1) of this subsection; or

                  (ii)      the request was submitted by the voter to the Motor Vehicle Administration, a voter registration agency, another local board, or the State Board before the beginning of the period specified in paragraph (1) of this subsection.

      (c)      If a registered voter has moved from one county to another within the State since the last general election, the voter may change party affiliation or change to or from a decline, one time only, during a period specified in subsection (b)(1) of this section.

      (d)      An individual whose registration has been canceled at the individual's request within a period specified in subsection (b) of this section may not reregister in the same county during the same period with a party affiliation or nonaffiliation different from the previous registration.