To delete a Preferred Agency from the Agencies page, click the menu to the right of the agency you wish to delete and select "Delete Agency". You will then be asked to confirm that you wish to remove the agency from your organization.

You can also delete a Preferred Agency from their profile card by clicking the menu, and then selecting "Delete Agency".

Deleting a Preferred Agency prevents the agency from working on your JobCasts at their custom fee for any JobCasts you create.  Any JobCasts that the Preferred Agency has previously been invited to will remain at their custom fees.