I'm redoing my bathroom and trying to figure out how to replace my toilet waste pipe. The flange is attached to a black pipe (unsure of the material), which runs into a cast iron hubbed fitting. I am unsure if I can just cut the pipe that is running off of the cast iron pipe and then use a banded coupling to PVC, or if I should completely pull the waste pipe out of the hubbed fitting and replace the whole thing. If the latter is suggested, how do I go about installing the pipe into the hubbed fitting and what materials are required? Thank you.