Custom insert() member function for std::vector of unique_ptr

I need a custom insert / add member function for my "entity manager class" which is only responsible of many entities. For this I define a std::vectorstd::unique_ptr<cEntity> listOfEntities as private in this class. But how can I add entities to the vector?

Following situation:

class cEntity
{
public:
    void setName(const std::string& newName) 
    {
        name = newName;
    };

private:
    std::string name;
};


class cEntityMgr
{
public:
    cEntityMgr() { listOfEntities.clear(); };
    void addEntity(const cEntity& aEntity)
    {
        listOfEntities.push_back(aEntity);     // this doesn´t work
    };
    

private:
    std::vector<std::unique_ptr<cEntity>> listOfEntities;
};


int main()
{
    //
    cEntityMgr myFirstEntityMgr;

    // add a new entity to my entity manager
     myFirstEntityMgr.addEntity(std::make_unique<cEntity>("My First Entity") );      // I don´t want to use any new call here
}