You can't since ownership "type" is recorded with the property. Although the unit is detached, because the property title is defined by the city prior to construction, it cannot be changed to something it's not by building code. Most often a detached home is called a "condo" when it is constructed on a smaller than allowed lot size by building codes of the city. Often the city also allows a larger than allowed home to be built on the property by using the condominium definition. To allow affordable and denser single family homes to be built, the city allows the homes to be called condos with the perimeter of the defined condo being the exterior lot lines of the property. This title would apply to all homes within the community, so neither you nor the other owners can change title without removing some homes and increasing lot sizes to at least 5500 SF and often decreasing square footage inside the home, in most cases. Sorry, but this is not going to be allowed.