Edit a a member of a list by touching the information icon on the list value selection screen when you are editing a record. The new values will propagate to all records that had the old value

You can delete an item from any list with a swipe delete on the item.  The only thing to keep in mind is that you cannot delete an entry from a list if that entry is already in use in a note.  If the value you are trying to delete is already in use in another note, the option to delete will not appear when you swipe the entry.

Here is something about the swipe delete for your information.  https://www.youtube.com/watch?v=C7TCK2fbP_E