At its meeting, the board of equalization shall proceed to equalize and correct the assessment roll. It may change the valuation and assessment of any real property upon the roll by increasing or diminishing the true and full valuation thereof as is reasonable and just to render taxation uniform, except that the board may not increase the valuation of any property returned by the assessor to an amount that results in a cumulative increase of more than fifteen percent from the amount of the previous year‘s assessment without first giving the owner or the owner’s agent reasonable notice and opportunity to be heard regarding the intention of the board to increase it. All complaints and grievances of residents of the city must be heard and decided by the board and it may make corrections as appear to be just. Complaints by nonresidents with reference to the assessment of any real property and complaints by others with reference to any assessment made after the meeting of the city board of equalization must be heard and determined by the county board of equalization. The board shall comply with any requirement for notice of an assessment increase under section 57-02-53.