Assign the specified newKey value to the pair identified by the specified reference, moving the pair within the list as necessary. Load into the optionally specified newFrontFlag a true value if the new location of the pair is the front of the list. Return 0 on success, e_NOT_FOUND if the pair referred to by reference is no longer in the list, or e_DUPLICATE if the optionally specified allowDuplicates is false and newKey already appears in the list.