The council may, from time to time, by a majority vote of all members of the city
council adopt amendments to this chapter, including the zoning map. Amendments which
change all or part of the existing classification of a zoning district from residential
to either commercial or industrial require a two-thirds majority vote of all members
of the city council. Amendments shall not be adopted that are inconsistent with the
city's comprehensive plan unless the council expresses its intent to amend the comprehensive
plan.