3x12 - Punky Brewster

Punky is invited to the birthday party of rich kid Robert Whitney when Henry is hired to be the party's photographer. In order to keep from embarrassing Henry, Punky takes lessons from Margaux on how to act like a rich stiff. The lessons don't work -- Punky ends up wreaking havoc and has Robert wishing that his social secretary Charles hadn't invited any stiffs to the party, because Robert didn't want the party to be as boring and stiff as Charles wanted it to be.