Merge pull request #4209 from MicrosoftDocs/master

12/6 AM Publish

Author: v-alje

docs/database-engine/availability-groups/windows/configure-distributed-availability-groups.md

@@ -205,6 +205,12 @@ ALTER AVAILABILITY GROUP [distributedag]
 GO  
 ```  
 
+## <a name="failover"></a> Join the database on the secondary of the second availability group
+After the database on the secondary of the second availability group has went into a restoring state you have to manually join it to the availability group.
+
+```sql  
+ALTER DATABASE [db1] SET HADR AVAILABILITY GROUP = [ag1];   
+```  
 
 ## <a name="failover"></a> Fail over to a secondary availability group  
 Only manual failover is supported at this time. The following Transact-SQL statement fails over the distributed availability group named `distributedag`: