Closed queries can be reactivated via the detail view or via the search menu.
Whether the ticket is really reactivated via a status change or automatically duplicated depends on how the global system configuration is set and whether the ticket to be reactivated has already been answered or not.
If it has already been answered, a complete copy with its own ticket ID will ALWAYS be created. If, however, the ticket has only been closed without an answer, then only the status will be set back to “in queue” – unless it is set via system configuration that a fixed copy will always be created!