Although both of them are white stews, they are not the same dish. A fricassee is made from poultry and other white meat, and the meat is just turned in fat but not browned before cooking in a white sauce.
For a blanquette, the meat or seafood is poached in stock and a sauce is made with the liquor after cooking, to pour over the meat.
Fricassee really should be made with fresh meat but sometimes using leftovers could also be an excellent way.
** Asian Recipes