If it is on tree fern, there isn't any good way to remove it from the tree fern without cutting off the roots. You can always attach more tree fern to the current mount, and the Phal's roots will grow into it. If it is a tree fern plaque, you can just take a larger plaque and attach it behind the original one with wire. I use the smallest aluminum wire for all of these kinds of projects, but whatever works for you.