There's some command where you can render a section into a sample, and then you can do tracker style pitch bends with effect commands to it.
But also since you just grabbed a demo you probably aren't that serious about renoise.
It's this. Uxx or Dxx. Render a couple octaves into an XRNI and go nuts. That and the render any pattern selection into a sample are some of my favorite features of Renoise. I liked the demo enough but, once I paid for the program, those two features really made it so much better, besides so many other things. 3.0 maybe coming soon, too.