With this action you can set a layer to use a different tileset from those in the resource tree. You give the name of the layer (a string, as defined in the Room Editor), and then the tileset resource to use, and all tiles in the room on that layer will be drawn with the new tileset.
Argument Description Layer The layer on which to set the new tileset. Tileset The tileset to use for the layer.
The above action block code checks to see if the tiles on the layer "Floor_Tiles" is using the tileset "tl_Palace", and if they not, then they are set to use it.