Complex sentence: When St. Louis returned to her home port of 32nd Street Naval Station San Diego, CA she received an overhaul and then changed home port to Sasebo, Japan where she remained doing Humanitarian Aid missions until she was decommissioned in 1992.
Split into simpler sentences: When St. Louis returned to the Home port of 32nsd Street Naval Station San Diego, CA. She received an overhaul and then was Re-Home ported to Sasebo, Japan where she remained doing Humanitarian Aid missions until she was decommissioned in 1992.