The PennState Olympian Elite is dead simple -- the nib and its feed are a push-fit into the section.
Simply grip the nib and feed firmly between thumb and first finger and pull straight out.
Then use a soft toothbrush and warm soapy water to clean away any crud that's built up in the channel along the top of the feed, and have a good look at the nib to see if there's crud sealing up the split between the tines.
Clean out the interior of the section.
Rinse all the bits in fresh water (distilled water if you want to be OCD about it), dry them off, and re-assemble. I do it by holding the nib upside down, position the feed centrally on it, then slide the nib & feed together into the section. There is a flat on one side of the feed which must match the flat inside the section.
HTH