minecraft-assets/data/minecraft/recipes/yellow_bed_from_magenta_bed.json

{
  "type": "minecraft:crafting_shapeless",
  "category": "building",
  "group": "yellow_bed",
  "ingredients": [
    {
      "item": "minecraft:yellow_dye"
    },
    {
      "item": "minecraft:magenta_bed"
    }
  ],
  "result": {
    "item": "minecraft:yellow_bed"
  }
}