diff --git a/mailerlite/campaign.py b/mailerlite/campaign.py
index 5eab9e9..7229022 100644
--- a/mailerlite/campaign.py
+++ b/mailerlite/campaign.py
@@ -240,7 +240,7 @@ def send(self, campaign_id):
         url = client.build_url('campaigns', campaign_id, "actions/send")
         return client.post(url, headers=self.headers)
 
-    def cancel(self, campaign_id):
+    def cancel(self, campaign_id, as_json=False):
         """Cancel a campaign which is in outbox.
 
         https://developers.mailerlite.com/reference#campaign-actions-and-triggers
@@ -249,6 +249,8 @@ def cancel(self, campaign_id):
         ----------
         campaign_id : int
             campaign id
+        as_json : bool
+            return result as json format
 
         Returns
         -------
@@ -258,7 +260,17 @@ def cancel(self, campaign_id):
         """
         # TODO: Check if campaign is in Outbox otherwise raise an issue
         url = client.build_url('campaigns', campaign_id, "actions/cancel")
-        return client.post(url, headers=self.headers)
+        code, res_json = client.post(url, headers=self.headers)
+
+        # TODO: Check new attribute to campaign object.
+        # if as_json or not res_json or code != 200:
+        #     return res_json
+
+        # res_json['opened'] = Stats(**res_json.pop('opened'))
+        # res_json['clicked'] = Stats(**res_json.pop('clicked'))
+
+        # return Campaign(**res_json)
+        return code, res_json
 
     def delete(self, campaign_id):
         """Remove a campaign.
diff --git a/mailerlite/tests/test_campaign.py b/mailerlite/tests/test_campaign.py
index ca80457..706fadc 100644
--- a/mailerlite/tests/test_campaign.py
+++ b/mailerlite/tests/test_campaign.py
@@ -9,6 +9,7 @@
 @pytest.fixture
 def header():
     headers = {'content-type': "application/json",
+               "X-MailerLite-ApiDocs": "true",
                'x-mailerlite-apikey': API_KEY_TEST
                }
     return headers
@@ -42,9 +43,11 @@ def campaign_data_ab():
 
 def test_wrong_headers(campaign_data):
     headers_1 = {'content-type': "app",
+                 "X-MailerLite-ApiDocs": "true",
                  'x-mailerlite-apikey': API_KEY_TEST
                  }
     headers_2 = {'content-type': "application/json",
+                 "X-MailerLite-ApiDocs": "true",
                  'x-mailerlite-apikey': 'FAKE_KEY'
                  }
     headers_3 = {'content-type': "application/json",
@@ -145,5 +148,5 @@ def test_cancel_send_campaign(header):
         assert res[0].status == 'outbox'
         code, res_2 = campaign_obj.cancel(res[0].id)
         assert code == 200
-        assert res_2.status == 'draft'
-        assert res[0].id == res_2.id
+        assert res_2["status"] == 'draft'
+        assert res[0].id == res_2["id"]