Protests are sustained unless overruled by two-thirds vote of the legislative body. The legislative body may sustain protests as to one portion, and overrule them as to another portion of park land. If protests are overruled, the legislative body may adopt an ordinance calling, and fixing the date of, a special election to submit to the city electors the question of discontinuance and abandonment of the use of park land on which protests were overruled.