How to turn boost::shared_ptr<> into a reference (&)?

So I have a class that uses references (&) with functions like

void request(tcp::socket& socket); 

I am starting migrating all my code to boost::shared_ptr but I would really like to know how to turn my shared_ptrs into references so to be capable to make my code evolve function by function and not in one iteration changing all I have into shared_ptr. So how to turn a shared_ptr into a reference?