The shocks don’t support any weight at ride height. You should be able to crawl under and unbolt them with the vehicle on its wheels. You may have to compress the shocks by hand to get them out and the new ones in but it’s not terribly difficult to do. Make sure you set the parking brake and leave it in gear (manual) or in park (auto) before crawling underneath. Consider blocking the wheels if you are on a slope.
If you can‘t reach them with the tires on, you can set the axles on jack stands and take the wheels off. It’s generally easier with the weight of the vehicle on the springs.
Do not unbolt anything but the shocks.