Drain it and then remove the center brace. The way on Melev's site will work but you better be careful. When I had a sump underneath my tank I removed a side of the stand so I could slide the sump in. I built my stand so I knew what I could remove without affecting the structure of the stand.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,