How to write a traits conversion to add 'const' to type*

Is it possible to have a traits in order to convert, let's say, char* to const char* in order to use it further to call functions having const char* parameters using a char* variable?

I have this (the context is large, I've simplified, sorry for the ugly code):

#include <iostream>
using namespace std;
#include <stdio.h>
#include <string.h>
#include <typeinfo>

template<typename T, typename U, std::enable_if_t<std::is_same<T, U>::value, int> = 0>
T convert_type(U _in)
{
    return _in;
}

template<typename T, typename U, std::enable_if_t<std::is_same<T, std::add_lvalue_reference_t<U>>::value, int> = 0>
T& convert_type(U& _in)
{
    return _in;
}

template<typename T, typename U, std::enable_if_t<std::is_same<T, std::add_lvalue_reference_t<std::add_const_t<U>>>::value, int> = 0>
T& convert_type(U& _in)
{
    return _in;
}

template<typename T, typename U, std::enable_if_t<std::is_same<T, std::add_pointer_t<U>>::value, int> = 0>
T convert_type(U& _in)
{
    return std::addressof(_in);
}

int main() {

    char* c = new char[sizeof "test"];
    strcpy(c, "test");

    const char * cc = convert_type<const char *, char *>(c); // here not compilable yet due to lack of the right convert_type specialization

    cout << c;

    delete[] c;
    return 0;
}

Just to clarify, I embed SpiderMonkey to script Illustrator API. This made me write pretty complicated code, but I have checked and I know the conversion traits above are in use for various function calls. I've added them here just to see the approach and to clarify the need of adding another that recognizes a type and returns the needed type. All your comments are correct generally, but not in my context. I might have a convoluted code, but I have simplified it as much as I could.

sample code here

As far as it concerns me, the question is not yet answered and I couldn't find a solution. I put the question this way: how to write a traits method to match char* against const char*, which is char const*, actually, when I check in msvc with typeid a type or variable declared as const char*?