diff --git a/arangod/Cluster/ClusterMethods.cpp b/arangod/Cluster/ClusterMethods.cpp
index 252e70c783..6da5679dd4 100644
--- a/arangod/Cluster/ClusterMethods.cpp
+++ b/arangod/Cluster/ClusterMethods.cpp
@@ -1860,7 +1860,7 @@ int modifyDocumentOnCoordinator(
 
   std::string baseUrl = "/_db/" + StringUtils::urlEncode(dbname) + "/_api/document/";
   std::string optsUrlPart = std::string("?waitForSync=") + (options.waitForSync ? "true" : "false");
-  optsUrlPart += std::string("&ignoreRevs") + (options.ignoreRevs ? "true" : "false");
+  optsUrlPart += std::string("&ignoreRevs=") + (options.ignoreRevs ? "true" : "false");
 
   arangodb::GeneralRequest::RequestType reqType;
   if (isPatch) {