I did mine a few months ago and jesus its a job! It requires removing wheel,jacking the bike up on wooden blocks under the slip-ons,removing rear sprocket (which is a job on its own),removing spindle,and then you can access the rotor. Give the whole lot a re-greasing/loctite where you should and repeat the whole process in reverse!!!
Good luck
FYI:
It is pretty easy.
Step 1 - Remove rear wheel, then brake caliper.
Step 2 - Remove rear sprocket setup by removing the 55mm nut. Sprocket setup will slide freely.
Step 3 - Tap the rear axle towards the wheel side, from the sprocket side, thats how it will be removed.
Step 4 - Pull the rear axle and brake rotor setup out.
Then just swap the rotor
Took 45 mins the first time. I could do it in 10 now.
Its very straight forward just as long you have either a friend that can hold the bike upright whilst balanced on wood blocks,or got an overhead hoist to suspend tail from!