Assuming this is a foreclosure (bank has seized the unsold units because the builder has not paid their construction loan). The lender will assign a Realtor to sell the unsold units. What I've seen happen in several multi unit foreclosures in Minneapolis is that there are liens against the property because the builder took the banks money and failed to pay contractors and sub contractors. This slows down the process considerably because technically there is a cloud on title as long as the liens are on the unsold units.

If it's a bankruptcy situation (builder filed chapter 7 or 11) I believe the bankruptcy judge will appoint a receiver who will attempt to sell the unsold units either in a block or individually, in order to satisfy the creditors involved in the bankruptcy.

In both instances look for discounts from the original sales prices to move the unsold units.