(a) Subject to § 8-103 of this article, the court may extend the period for which alimony is awarded, if:
(1) circumstances arise during the period that would lead to a harsh and inequitable result without an extension; and
(2) the recipient petitions for an extension during the period.
(b) Subject to § 8-103 of this article and on the petition of either party, the court may modify the amount of alimony awarded as circumstances and justice require.