Purchased two new replacement filters (part number may have been upgraded). My wife pushed in the old filter, which causes it to automatically pop back out, She then plugged in the new part, keeping the other one for a “spare”! We then ran one or two large glasses of water from the exterior freezer section Water fill nozzle. There was a “large” flush out which cleaned the old lines.
All is now functioning as it should. The entire process took less than ten or fifteen minutes and didn’t require unplugging the Refigerator at the rear. Note: we had already taken off the freezer side bottom piece to clear it of dog hair, etc. That allows clean air to be drawn up into the freezer tubing. It’s hard to explain in words... watch a video on YouTube. It’s a ten minutes of time process.