It's a bit of a bugger to do.
I've done 1 and it took nearly a day to get all the bits of old pipe out the rack connection. It's actually best to replace the whole hose assembly, as once it's done, it'll outlast the vehicle, if you paint the metal pipes when they're fitted.
Thankfully mine is currently ok, so I'm hoping to avoid that little joy for a couple of years yet.
Make sure you replace the reservoir at the same time, as the built in filter blocks, causing it's own issues, and only used the correct CHF fluid, which is normally green or clear in some makes.