diff --git a/src/applications/differential/xaction/DifferentialRevisionCommandeerTransaction.php b/src/applications/differential/xaction/DifferentialRevisionCommandeerTransaction.php
--- a/src/applications/differential/xaction/DifferentialRevisionCommandeerTransaction.php
+++ b/src/applications/differential/xaction/DifferentialRevisionCommandeerTransaction.php
@@ -59,11 +59,21 @@
   }
 
   protected function validateAction($object, PhabricatorUser $viewer) {
-    if ($object->isClosed()) {
+    // If a revision has already landed, we generally want to discourage
+    // reopening and reusing it since this tends to create a big mess (users
+    // should create a new revision instead). Thus, we stop you from
+    // commandeering closed revisions.
+
+    // See PHI985. If the revision was abandoned, there's no peril in allowing
+    // the commandeer since the change (likely) never actually landed. So
+    // it's okay to commandeer abandoned revisions.
+
+    if ($object->isClosed() && !$object->isAbandoned()) {
       throw new Exception(
         pht(
           'You can not commandeer this revision because it has already '.
-          'been closed. You can only commandeer open revisions.'));
+          'been closed. You can only commandeer open or abandoned '.
+          'revisions.'));
     }
 
     if ($this->isViewerRevisionAuthor($object, $viewer)) {