In Arizona, a developer who wants to build a mixed-use project with retail on the ground floor and residential above in a residential-only zone would need to apply for:

Local government regulations that control land use by dividing areas into zones specifying permitted uses, building sizes, and densities.

Official permission to use land in a way that does not conform to the applicable zoning ordinance, granted by a zoning board when strict enforcement would cause undue hardship.

The power of government to take private property for public use, with the requirement to pay the owner just compensation.

A doctrine by which a person can gain legal title to another's land by openly, continuously, and adversely occupying it for a statutory period.