this section shall be subject to valid existing rights. (h) Title approval Title to the real property described in subsection (a) and the real property described in subsection (b) to be exchanged under this section shall be in a form acceptable to the Secretary. (i) Treatment of acquired land Land and interests in land acquired by the United States under subsection (b) shall be administered by the Secretary as part of the Gulf Islands National Seashore. (j) Modification of boundary Upon completion of the land exchange under this section, the Secretary shall modify the boundary of the Gulf Islands National Seashore to reflect such land exchange.