When & how do you prune a desert rose plant?
Pruning a Desert Rose
Certified GKH Gardening Expert
Usually, you will not have to do this. You can prune dead growth out, or prune to take cuttings, but this is not necessary for its health. I would do this during the time that it is not actively growing or after the flowers fade.
Here is an article for more information on this plant: https://www.gardeningknowhow.com/ornamental/flowers/desert-rose/caring-for-desert-rose-plants.htm