The undo activity and the activity being undone MUST both have the same actor.

{
  "id": "urn:uuid:64d00f29-b0f5-4407-963f-5dce7c7dae2e",
  "uuid": "64d00f29-b0f5-4407-963f-5dce7c7dae2e",
  "type": "Behavior",
  "content": "The undo activity and the activity being undone MUST both have the same actor.\n",
  "tag": [
    {
      "name": "ActivityPubClient",
      "id": "https://socialweb.coop/tag/ActivityPubClient"
    }
  ],
  "context": [
    "https://www.w3.org/TR/activitypub/",
    {
      "name": "6. Client to Server Interactions",
      "id": "https://www.w3.org/TR/activitypub/#client-to-server-interactions"
    },
    {
      "name": "6.10 Undo Activity",
      "id": "https://www.w3.org/TR/activitypub/#undo-activity-outbox"
    }
  ],
  "origin": {
    "source": "https://www.w3.org/TR/activitypub/",
    "section": {
      "id": "https://www.w3.org/TR/activitypub/#undo-activity-outbox",
      "name": "Undo Activity",
      "branch": [
        6,
        10
      ]
    },
    "selector": {
      "type": "TextQuoteSelector",
      "prefix": "The Undo activity is used to undo a previous activity. See the Activity Vocabulary documentation on Inverse Activities and \"Undo\". For example, Undo may be used to undo a previous Like, Follow, or Block. \n",
      "exact": "The undo activity and the activity being undone MUST both have the same actor.\n",
      "suffix": "Side effects should be undone, to the extent possible. For example, if undoing a Like, any counter that had been incremented previously should be decremented appropriately. \n"
    }
  },
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://socialweb.coop/ns/testing/context.json"
  ]
}