Find Customer Referee

Task: Find the names of the customer that are not referred by the customer with id = 2.

Table: Customer

+-------------+-------------+
| Column Name | Type        |
+-------------+-------------+
| id          | INT         |
| name        | varchar(25) |
| referee_id  | INT         |
+-------------+-------------+

Input: Customer table:

+----+------+------------+
| id | name | referee_id |
+----+------+------------+
| 1  | Will | null       |
| 2  | Jane | null       |
| 3  | Alex | 2          |
| 4  | Bill | null       |
| 5  | Zack | 1          |
| 6  | Mark | 2          |
+----+------+------------+

Output:

+------+
| name |
+------+
| Will |
| Jane |
| Bill |
| Zack |
+------+