diff --git a/.github/workflows/validation.yml b/.github/workflows/validation.yml
index d48c9a347..c5dd5964a 100644
--- a/.github/workflows/validation.yml
+++ b/.github/workflows/validation.yml
@@ -36,6 +36,15 @@ jobs:
         steps:
             - uses: actions/checkout@v4
 
+            - name: Get Modified JSON Files
+              id: modified_files
+              run: |
+                  MODIFIED_FILES=$(git diff --name-only ${{ github.event.before }} ${{ github.sha }} | grep '^domains/.*\.json$' | sed 's|.*/||' | tr '\n' ',' | sed 's|,$||')
+                  echo "MODIFIED_FILES=${MODIFIED_FILES}" >> $GITHUB_ENV
+
             - run: npm install
 
             - run: npm test
+              env:
+                  PULL_REQUEST: ${{ github.event.pull_request.number || false }} # false if not a PR
+                  MODIFIED_FILES: ${{ env.MODIFIED_FILES }}
diff --git a/tests/pr.test.js b/tests/pr.test.js
new file mode 100644
index 000000000..6e5588fd7
--- /dev/null
+++ b/tests/pr.test.js
@@ -0,0 +1,23 @@
+if (!process.env.PULL_REQUEST) return;
+
+const t = require("ava");
+const fs = require("fs-extra");
+const path = require("path");
+
+const PR_AUTHOR = process.env.PR_AUTHOR;
+const MODIFIED_FILES = process.env.MODIFIED_FILES.split(",");
+
+const domainsPath = path.resolve("domains");
+
+const admins = require("../util/administrators.json");
+
+t("Modified JSON files must be owned by the PR author", (t) => {
+    MODIFIED_FILES.forEach((file) => {
+        const domain = fs.readJsonSync(path.join(domainsPath, file));
+
+        t.true(
+            domain.owner.username === PR_AUTHOR || admins.includes(PR_AUTHOR),
+            `${file}: Owner should be ${PR_AUTHOR} but is ${domain.owner}`
+        );
+    });
+});
diff --git a/util/administrators.json b/util/administrators.json
new file mode 100644
index 000000000..f85832ced
--- /dev/null
+++ b/util/administrators.json
@@ -0,0 +1,4 @@
+[
+    "wdhdev",
+    "DEV-DIBSTER"
+]
\ No newline at end of file
diff --git a/util/reserved-domains.json b/util/reserved-domains.json
index 67087b209..42a683c8c 100644
--- a/util/reserved-domains.json
+++ b/util/reserved-domains.json
@@ -8,7 +8,9 @@
     "api",
     "auth",
     "authentication",
+    "authorisation",
     "authorise",
+    "authorization",
     "authorize",
     "aux",
     "billing",
@@ -17,6 +19,7 @@
     "cart",
     "catalog",
     "checkout",
+    "co",
     "com",
     "com[1-9]",
     "con",
@@ -74,7 +77,6 @@
     "payments",
     "portal",
     "postmaster",
-    "prn",
     "recovery",
     "redirect",
     "registrar",