arangosh> a1 = db.example.insert({ a : 1 }); { "_id" : "example/111294", "_key" : "111294", "_rev" : "_YYClW9W--_" } arangosh> a2 = db.example.replace(a1, { a : 2 }); { "_id" : "example/111294", "_key" : "111294", "_rev" : "_YYClW9W--B", "_oldRev" : "_YYClW9W--_" } arangosh> a3 = db.example.replace(a1, { a : 3 }); [ArangoError 1200: precondition failed]