A short script can reduce the need to recall every point during a call. You can pause, ask for repetition, end the call, write instead or invite someone to sit with you; the aim is a useful conversation, not perfect delivery.
Write the reason and desired outcome first, then keep up to three points and the question that matters beside the phone. The separate script card lets you carry only the words you choose.
Optional and private. Writing an email instead is fine, and so is asking someone to sit with you. Any call can be ended.