If you have appointed 2 donees to act jointly (all decisions have to be agreed by both donees) and not jointly and severally (either one of your donees can make decisions for you), and one of the donees passes away or can't be a donee for some reason, without a replacment donee, your Lasting Power of Attorney (LPA) will be cancelled .

If you have included a replacement donee in your LPA to replace one of your joint donees, then the replacement donee will take over the duty of the joint donee who passed away or can't be a donee for some reason.