I am amending a 2018 1040. My client wants to have both myself, the paid preparer, and an associate of my client's listed as a Third Party Designee. When I do not have the other individual entered on screen 3 under the Designee/IRS Discussion, the checkbox beside my name on the face of the return identifying myself as the Third Party Designee is checked. However, as soon as I fill in the information for the other individual the box is unchecked. Is it possible to have an individual listed on Schedule 6 and have the paid preparer as a Third Party Designee?