Rear Brake Caliper Rebuild

I had my brakes heat up and lost all brakes so I decided to rebuild my calipers with new seals. Got the front done no problem but I’m not completely sure how to remove pistons from rear brake caliper. I have read you can use air and or grease but have not seen any input on my type of caliper with 2 pistons. Any input would be greatly appreciated. Here is a picture of the brake caliper I have.