You need a different product (several are available) to split the PDF to remove pages. The free Adobe Reader (or reader clones) won't do it.
I had on product for a long time that did it but I dropped it when java had so many security issues. It required java. The one I use now had limitations and weird typos but it does split or merge PDF files.
I think I just answered that question. Check your other thread. I may have to figure out how to merge threads in this board software. I've not tried that before.