Arngrim left the series at the end of the seventh season. Nellie's resulting departure was explained by having her move with Percival and their twins to New York to run the family business when Percival's father falls ill; the move is made permanent when Percival's father dies. After Nellie's departure became permanent, the Olesons adopted a daughter named Nancy (played by Allison Balson), who bore a striking resemblance to Nellie, although she had a nastier and meaner disposition than Nellie.
Arngrim departed from the series at its seventh season conclusion. This led to Nellie relocating to New York with Percival and their twins to manage the family business when Percival's father falls ill; this move is made permanent after Percival's father passes away. As a result, the Olesons adopt a daughter named Nancy (played by Allison Balson), who bears an uncanny resemblance to Nellie but possesses a more unpleasant and malevolent personality.