The main trick to re-taping or accomplishing a major patch on a sand texture is removing the texture from the area before beginning. Scrape away as much of the texture as possible from around the damaged area. How much depends on the patch, typically 3 inches around the area to be patched.
The reason for the scraping is to allow room for the drywall tape and 2 coats of drywall mud without creating a large bump that will be very visible when re-textured and painted. Matching this type of texture can be challenging. If possible use the same type of sand paint used previously and apply in the same manner for the best match.