The exact location (pun intended) will depend on the Primo or Nextgen version/release you are using..there is some variance within the Save folder(s), so you may have to hunt around a bit.
One example would be Save/Profiles/01/userlists. There you will probably see 4 files: locations_A.txt, locations_A.txt.cks, locations_B.txt, and locations_B.txt.cks. The "A" files tend to be (but not always) Home, and the "B" files tend to be Work. Delete all 4 and you can then re-enter Home and Work within the program. Delete just the "A" files and you may be able to keep Work and just re-do Home...and vice-versa. Maybe.