These scenarios usually have multiple sides to them. The problem is that traditional commercial lenders will lend based on the current value or purchase price (which ever is the lower). So in order for the deal to close the remaining balance has to brought to closing.
This is usually done by utilizing lines of credit, equity partners, or subordinate financing or any combination of. If structured properly a no money down scenario can be created if the original buyer is willing to share some equity hence reducing his/her profit.