Hello,
In order to to have easy access to the locking tab of the balljoint, I think it is better to remove the caliper.

When removing and than replacing it, is it necessary to do anything with the pads?
Thank you

I always remove the calliper when I change balljoints. not because I cannot undo the locking tap/plate of the balljoint with it in place, but because when I change them I remove the disk and hub completely from the car as I find it nearly impossible with my air tools to undo the balljoints on the car, so I take the hole hub out of the car with the two balljoints in place and the bearings inside and put it in the vice and leave the suspension arms, driveshaft, cv joint and everything on the car.

Since I have never removed a caliper, my question is this:
Except of unscrewing the two bolts of the caliper, is it necessary to do something with the pads, like removing or manipulating them in any way, before removing/ replacing the caliper?

undo both bolts. push back the pistons a little to ease removal. you don't need to remove the pads but can do to avoid getting brake fluid on them. undo both pipes from the hoses and plug the pipes with something so that the brake fluid doesn't leak out which makes bleeding harder. undo the hoses from the car. remember which pipe each hose goes to. remove the calliper with hoses and undo the hoses from the calliper. put it all back together with the new calliper. bleed very thoroughly and at least twice as long as you would normally. take all on all three bleed nipples and put copper grease on them. preferably use a pressure bleeding device as bleeding via the pedal can be troublesome if your master cylinder is worn.

Thank you very much for your clear and detailed explanation.