If my half caliper still has the pistons in then it's a case of splitting your caliper after removing the pads and clips. Brake fluid will come out so watch out.
Fit a new tiny o-ring that goes between the caliper halves or use the old one if it looks ok then offer up my half caliper, refit the bolts holding the caliper halves together.
Finish by bleeding as normal then refit pads and clips.
If my half caliper is without pistons then it's a wee bit trickier but not too bad.
I'll check my half caliper to see if the pistons are still in it and let you know.