Changing how a sim died without resurrecting them first

[Kitten]

How can you change the type of ghost a sim has (drowned,disease, etc) without having to resurrect them and kill them again? I know you can change this using boolprop, but that doesn't have any options introduced by eps (eg. cowplant, murphy bed). More specifically, I want to make a sim die of old age then change the sim's death type, while keeping the platinum aspiration gracestone/urn.

[J. M. Pescado]

It doesn't really matter. Death type will be lost when you move the tombstone anyway.