If you want to delete an FTP account, you can accomplish it by following this tutorial.
1. Log in to your cPanel account.
2. In the Files section, click on FTP Accounts.
3. Under the FTP Accounts list, choose Delete.
4. Click on Delete once again to confirm and remove the FTP account.
Delete the Users Home Directory option should not be used. In the absence of a backup, the data in your FTP user account will also be destroyed and rendered inaccessible.