Regulations, restrictions, and boundaries may be amended, supplemented, changed, modified, or repealed from time to time. If a protest against a change, supplement, modification, amendment, or repeal is signed by the owners of twenty percent or more:

1. Of the area of the lots included in such proposed change; or

2. Of the area adjacent, extending one hundred fifty feet [45.72 meters] from the area to be changed, excluding the width of streets,

the amendment shall not become effective except by the favorable vote of three-fourths of all the members of the governing body of the city. The provisions of section 40-47-04 relating to public hearings, official notice, and publication of regulations, restrictions, and boundaries shall apply equally to all changes or amendments provided in this section; provided, that protests in writing must be filed with the city auditor prior to the time set for the hearing.