Here's the quote (Mrs Norris, regarding what room will be assigned little Fanny): "close by the housemaids, who could either of them help to dress her, you know, and take care of her clothes, for I suppose you would not think it fair to expect Ellis to wait on her as well as the others. Indeed, I do not see that you could possibly place her anywhere else.”

Ellis is clearly a servant, not someone visiting MP. There is another example of "waited on" used in this sense in Chapter 22 of MP.