My yucca plant came as a larger one and a smaller one in the same pot. I've left them together but the larger one is dying. Its trunk is hollow when you tap it, unlike the smaller one which still sounds solid. Also, with the larger one, only two leaves are left sprouting out of it and they are now starting to turn yellow. I replanted both into a larger pot a few weeks ago hoping that would improve the bigger one but it seems not. Any advice would be great. Thanks.
You should have success removing the pup from the plant and repotting it in a separate pot.
Make sure you don't use to large of a pot as this can lead to overwatering and root rot.
Here is a link to refresh you on the care requirements.