Yes, you can absolutely leave and re-enter Disney World parking lots on the same day without paying twice. When you pay for parking at any of the four main theme parks (Magic Kingdom, EPCOT, Hollywood Studios, or Animal Kingdom), your pass is valid for the entire day across the whole resort. If you decide to go back to your hotel for a midday nap or move your car to a different park for "Park Hopping," you simply need to show your original parking receipt (or scan your MagicBand/ticket if linked) at the next toll plaza to gain entry. This "all-day" pass makes it very convenient for families to take breaks. It is important to keep your physical paper receipt handy, just in case the digital system has a sync delay at the next gate.