RCC++ is not intended to be used in a threaded manner, but this doesn't stop RCC++ from being used by programs with threading. For example the articles I've written on my open source threaded task enkiTS scheduler
http://www.enkisoftware.com/devlog-enkits.html feature images from my game Avoyd which uses RCC++.
Reloading one thread doesn't make much sense, as the distinction between threads and processes is that threads share the same memory space. I would advise stopping all active tasks/jobs (or threads if using a threading model) before swapping code.
Let me know if you need any help, and do look at enkiTS for your threading needs - I use it alongside RCC++, and might be able to make a sample of how to do that if it's of interest.