diff --git a/tidy.Rmd b/tidy.Rmd
index 19f0f83..654335e 100644
--- a/tidy.Rmd
+++ b/tidy.Rmd
@@ -503,7 +503,7 @@ We need to make a minor fix to the format of the column names: unfortunately the
 
 ```{r}
 who2 <- who1 %>% 
-  mutate(names_from = stringr::str_replace(key, "newrel", "new_rel"))
+  mutate(key = stringr::str_replace(key, "newrel", "new_rel"))
 who2
 ```