If the district shall file its objections in the manner aforesaid to the annexation of said territory or any specified portion or portions thereof to the district, said territory, or the portion or portions thereof so objected to, shall not be annexed to the district except in the manner provided in the District Reorganization Act of 1965 (commencing at Section 56000, Government Code). Prior to the expiration of the 90 day period referred to in Section 13911, the district may from time to time withdraw such objections to the annexation of said territory or any specified portion or portions thereof by filing with the city clerk a certified copy of a resolution or resolutions of the board stating that such objections to the annexation of said territory or any specified portion or portions thereof are withdrawn. Thereupon said territory, or the portion or portions as to which such objections are so withdrawn, shall be deemed incorporated into and annexed to the district as provided in Section 13911. Any such resolution or resolutions filed with the city clerk withdrawing the district’s objections to the annexation of a portion or portions of said territory shall describe such portion or portions.