Hi @Mark_Lewis, I don’t think you can do that directly in the task; anything there will be shared.
Alternative #1: Create a private task (perhaps in My Tasks) pointing at the shared task; this approach streamlines that procedure:
Alternative #2: Multi-home the task in a private project of yours:
Hope one of those might help!
Larry Berger
Asana2Go & Asana Certified Pro consultant at Trilogi