How do you change the oil pump on a 2004 ford e250 van?

To change the oil pump on a 2004 Ford E250 van, start by disconnecting the battery and draining the engine oil. Next, remove the oil pan by unbolting it from the engine block, which may require lowering the exhaust or other components for access. Once the oil pan is off, unbolt the old oil pump and replace it with the new one, ensuring to use a new gasket. Finally, reassemble the oil pan, refill with oil, and reconnect the battery.