Final answer:
A change in zoning designation to a more restrictive use could grandfather an existing apartment building, limiting expansion or redevelopment but allowing current operations to continue, while potentially leading to displacement due to gentrification and rising property values.
Step-by-step explanation:
When a zoning designation that allowed multiple dwellings is changed, it can significantly impact an existing apartment building within the area. If the new zoning restricts the area to single-family homes or otherwise imposes more restrictive uses, the apartment building may be grandfathered in under the previous zoning designation, allowing it to continue operating. However, this change could limit the building's potential for expansion or redevelopment in accordance with the new zoning rules. Furthermore, should the apartment building require significant renovations or rebuilding in the future, the new zoning regulations could prevent this, which might effectively freeze the current use. Displacement of residents and businesses due to gentrification and rising property values often accompanies such zoning changes, especially if they are part of broader urban renewal efforts.