sql server delete records that have a single duplicate column

1WITH cte AS (
2    SELECT 
3        contact_id, 
4        first_name, 
5        last_name, 
6        email, 
7        ROW_NUMBER() OVER (
8            PARTITION BY 
9                first_name, 
10                last_name, 
11                email
12            ORDER BY 
13                first_name, 
14                last_name, 
15                email
16        ) row_num
17     FROM 
18        sales.contacts
19)
20DELETE FROM cte
21WHERE row_num > 1;
22