A server rack is heavy, top-heavy when loaded, and packed with expensive, mission-critical equipment tied together by dense cabling. Moving it fully loaded risks both a dangerous tip and damage to the gear. The safe method is to back up everything, remove the equipment so the rack is manageable, and label the wiring meticulously so the system comes back online without guesswork.
Pro tip: Keep a written inventory and a cable map so reassembly and troubleshooting at the new site are straightforward.
Watch out: Never move a fully loaded server rack. It is dangerously top-heavy and can tip, injuring people and destroying equipment.