Robert's Rules of Order (10th Edition) Suspending or Amending the rules takes
a 2/3's vote. The relevant section is on page 600 which deals with rules
for conventions.
Erm... usually, By-laws, Party Rules or whatever they call their documents usually take precedence over RRO, not to mention that every state party's by-laws are different.
I'd read everything. You can't just read one book and claim you have known everything to be known about the proceeding.