Can you copy Derived Class objects from one std::vector

I have two vectors in C++, I register derived classes, then want to make copies and copy them over to active, I am trying to do this to avoid base class slicing but be able to have "templates" of classes that I use to spawn new objects that I can mutate from those. How do I clone an object pointed to by unique_ptr and have a new unique_ptr that I can store in a vector? The idea shown below is that I could have multiple copies of the class active, while still having the original copied object in available. Or is there a better architecture for trying to make copies of a derived class for storage?

#include <iostream>
#include <memory>
#include <vector>

class BaseClass {
    virtual void doSomething(){}
};
class DerivedClass1: public BaseClass {
    public:
    float myVar1;
    void doSomething() override { std::cout << "1"; }
};
class DerivedClass2: public BaseClass {
    public:
    int myVar2;
    void doSomething() override { std::cout << "2"; }
};

std::vector<std::unique_ptr<BaseClass>> available;
std::vector<std::unique_ptr<BaseClass>> active;

void registerClass( std::unique_ptr<BaseClass> newAvailable ) {
    available.push_back(std::move(newAvailable));
}
void makeActive() {
    for( auto &toMakeActive : available ) {
//        todo: ?? // active.push_back( available->clone() );
    }
}
int main() {
    std::unique_ptr<DerivedClass1> derived1 = std::make_unique<DerivedClass1>();
    std::unique_ptr<DerivedClass2> derived2 = std::make_unique<DerivedClass2>();
    registerClass( std::move( derived1 ) );
    registerClass( std::move( derived2 ) );

    makeActive();
    makeActive();
   return 0;
}