C++ change vector after a clear

i have the following C++ class:

   class N
      {
        private:
            vector<F> setF;
         public:
           Node(vector<F>* f) { setF = *f;};
           vector<F>* getSetF() { return &setF; };
           void setSetF(vector<F> input) { setF= (input); };
            };

Now, I create an object, namely obj of type N. Then I create a new vector of type N, namely avector, that should replace the vector inside obj. So, I write:

   vector <F> *sta =obj->getSetF(); 
   delete(sta);
   obj->setF(avector);

Now the vector inside obj has size 0, hence the replacement of the vector failed, but I don't know why. Any help ?