I need a code that can help me how to eliminate the rows numbers: 3 and 11 as this example, because its a recommended_sku already recommeded for person1 and person7

PLEASE RUN THIS:
X3 <- data.frame(ID = c("Person1","Person1","Person1",
"Person3","Person4","Person5",
"Person5", "Person6", "Person6",
"Person7","Person7","Person7",
"Person8","Person9", "Person9",
"Person10","Person11","Person11"),
Recommend_sku = c(1,2,2,1,4,5,
2,3,4,5,5,6,
4,3,2,1,2,3))
X3
"ELIMINATE THE ROWS 3 and 11" (Blue)
Or in more simply words: "eliminating Recommend_sku when is repeated by ID"
Blue:
person1 have already recommended_sku 2 (For that I need to eliminate that row 3)
person7 have already recommended_sku 5 (For that I need to eliminate that row 11)
If you have the solution, help me, please.
that data frame it´s just an example, I need to do that in my real data 2.500.000 of rows.
Thank you!!