Anna and Alto are the servants that were chosen from Liselotte to be taken with her for her new life. Though the different personalities they have, Liselotte always tries to accomodate both of them and gets along very well with Anna. Alto is a tsundere, so he never admits his feelings for her, though he is very attached to his master.
Liselotte, anyway, considers them as friends, and not as servants. That's why she's always very cheerful and would make everything to make them happy.
Both of them call her with the onorific "-sama", though Anna shorten her name calling her just "Lise-sama".