On Sabrina the teenage witch episodes when is living in her aunts house with Roxy and Morgan what happened to aunts?

In the Sabrina the Teenage Witch episodes where Sabrina is living in her aunts' house with Roxy and Morgan, her aunts, Hilda and Zelda Spellman, are not present. It is explained that they have gone on a long vacation and will be away for several episodes. During their absence, Sabrina is left in charge of the household and must take care of Roxy, her cousin, and Morgan, a talking cat.