You should be on ext of stay employment, once you get termination letter, cancel WP, cancel work visa and immediately switch over to ext of stay retirement. You need to prepare to meet the list of documents your IP needs ....go ask for a list at the offoce you are using.
While you are working, you are on yr ext of stay employment once you finished employment u can switch over to ext of stay retirement in the country. You cannot be holding both at the same time.