LPT Request: How do I separate with the person who cleans our house and also cleans and house sits for other family members?

Very nice person cleans my parent's house and also petsits for them. My partner and I recently decided to have them clean our house as well. They don't do a great job. Even after repeated requests for specific issues they miss quite a bit and I end up cleaning a lot afterward. I don't know how to politely let them know we don't need their services anymore without causing some awkwardness between them and our other family members.