if your flight has a PE cabin you can upgrade with miles from Y to PE. It should be 12000 per sector.

if eventually the plane with PE gets swooped out, there is a possibility to get downgraded if J is already full at which you will be due a refund of your asiamiles

CX502 has been operated with 77Ps in the last 7 days and CX597 have been operated with 33Ps 5 out of the last 7 days just for reference.