Change the oil with the engine at full operating temperature and just start it up. Watch the gage for pressure before you increase revs above idle. There is more than enough oil in the bearings to lubricate them at idle speed for the several seconds it might take for feed pressure to reach normal.

Here's another tip. If you have an "upside down" spin on filter removing it will cause a HUGE mess. To preclude this, puncture the top with a punch or big nail. Then open the pan drain plug and let the oil drain for at least five minutes. After you've installed the plug, you can remove the filter and almost not oil will be lost, and if you wrap a couple of shop rags around the oil filter boss, they should catch any drips.

If you have a replacable cartidige filter, fill the housing a about half full of oil before you install the new cartridge then top it off and install the lid. Even it it's up high, the oil won't drain down past the oil pump gears until the cows come home.

Duke