change default values

Found solution, which works great:

function my_em_modify_default_ticket($EM_Ticket) {
        if ( empty($EM_Ticket->ticket_id) ) {
            //you can modify any property in $EM_Ticket such as spaces or the ticket name, add or delete lines as necessary
            $EM_Ticket->ticket_spaces = 1; //ticket spaces
            $EM_Ticket->ticket_name = 'Custom Ticket Name';  //ticket name
            $EM_Ticket->ticket_description = 'Ticket Description';  //ticket description
            $EM_Ticket->ticket_price = 1; //ticket price
            //etc.
        }
}
add_filter('em_ticket', 'my_em_modify_default_ticket', 10, 2);