I am not sure what do you mean by "stop" but I've done similar things using C some 20 years ago, here's the general idea: You should have spare memory space to

I am not sure what do you mean by "stop" but I've done similar things using C some 20 years ago, here's the general idea: You should have spare memory space to accept updates, there are solutions for in-place updates but that will make things more complex so let's skip that. Once the new piece of code is in place you replace or insert an assembly jump instruction to your new code and you're good to go. This can replace the whole code, but if done smartly can replace parts of it. Think for example of using a dynamic jump table into functions.