The pilot The Female Instinct (1972) established Barney as being the sisters' chauffeur. For this first episode of the series not only was the role recast with Lou Antonio replacing Art Carney but the character's background and mindset was changed.
In the pilot Barney was an ex-cop hired by Lieutenant Ostrowski to keep the sisters out of trouble and prone to strenuously objecting to their investigation tactics (by bellowing "wrong!").
In the series while still the chauffeur and under orders by Ostrowski to not let them out of his sight, Barney is now an ex-con on parole who raises minor objections but more readily goes along with their ploys and subterfuges.
In the pilot Barney was an ex-cop hired by Lieutenant Ostrowski to keep the sisters out of trouble and prone to strenuously objecting to their investigation tactics (by bellowing "wrong!").
In the series while still the chauffeur and under orders by Ostrowski to not let them out of his sight, Barney is now an ex-con on parole who raises minor objections but more readily goes along with their ploys and subterfuges.