You dont need to cycle the ESP pump to bleed the brakes or to change the fluid.
I tried to bleed the system with an eezibleed when we first got the car, as i'd changed the rear calipers. Being lazy i figured the front tyre was as good a source as any and clipped it on there without letting it down to 10psi. The resovoir split and blew brake fluid all over the windscreen and scuttle panel.
I picked up a resovoir from an audi 80 at the scrapyard, which had the same fittings but was slightly smaller, swapped them over carefully and topped it up with new fluid slowly to ensure no air made it into the MC. Brakes worked fine afterwards. A week later bled it again with the eezibleed to get the new fluid thru the pipes to the front calipers, this time at a more sensible 10psi, which worked just fine. At no point did i touch the ABS pump.
The only time you'd need to cycle the pump is if you managed to get air inside the pump itself, for example by completely draining the system.
If you want to change the fluid, what i'd do is carefully empty the resovoir (it might be easier to simply remove it and drain it, if your careful you wont get any air into the cylinder) then fill with fresh fluid and bleed a reasonable amount thru to each caliper.
