If the only vanes that need to be done are the cone vanes, then it's possible to do it with the rotor still in the machine but a real pain. If you have a good system of pulling the rotor, I would definitely do that then you can inspect the cone vanes, the cone itself, and the rest of the transition vanes. We have a plasma cutter that you can set up to gouge the heads off the vane bolts off with and it only takes about 5 minutes to have the heads all gouged off and the vanes popped out. Sure beats using a wrench!