If you think the ceiling texture is water soluble you should have no trouble scraping it off. Just spray the ceiling to get the texture damp...let it sit for a little while to soften. Then scrape it off with a wide paint scraper. Since your ceiling is concrete you have nothing to worry about in terms of damaging it, so scape away. For sure this is a diy job. Just be aware that the concrete may not have a perfect finish to it ( which is one reason they often texture a concrete ceiling). Depending on what that concrete looks like ( and what you are looking for) you may end up having to cover it again.