Assume A has a right to claim money from B, arising from a contract or any other source of obligation. A might sell that right to C. The sale of the right is a contract, or obligationary agreement that obliges A to transfer the right to C.The sale itself does not transfer the right; that is achieved by cession, which in theory is a separate agreement entailing concurring intentions: to transfer the right on A's part and to take transfer of it on C's part.Du Plessis, et al. p.5.
