Colo. Rev. Stat. § 30-28-116
From time to time the board of county commissioners may amend the number, shape, boundaries, or area of any district, or any regulation of or within such district, or any other provisions of the zoning resolution. Any such amendment shall not be made or become effective unless the same has been proposed by or is first submitted for the approval, disapproval, or suggestions of the county planning commission. If disapproved by such commission within thirty days after such submission, such amendment, to become effective, shall receive the favorable vote of not less than a majority of the entire membership of the board of county commissioners. Before finally adopting any such amendment, the board of county commissioners shall hold a public hearing thereon, and at least fourteen days' notice of the time and place of such hearing shall be given by at least one publication in a newspaper of general circulation in the county.
C.R.S. § 30-28-116