NRS upgrade and impact on reservations

National Reservation Service Upgrade
From 00:01 hrs on Saturday 29 May 2010 until 11:00 on Sunday 30 May 2010, upgrade work will be carried out on the National Reservations Service (NRS). This period has been chosen as, whilst it is a busy period for travelling, it is one of the quietest times of the year for booking tickets.
NRS is the central reservations system managed by ATOC on behalf of Britain's train companies. Each year NRS processes 1.5 billion booking enquiries from station ticket offices, ticket sales websites, call centres and travel agents. These searches result in over 60 million reservations every year made on National Rail train services in Great Britain. It also supports the sale of over half a million great value Advance fares every week.
The upgrade will double the capacity of NRS, allowing it to support further increases in the already fast growing number of Advance tickets sold every week as well as the anticipated further growth in seat reservations. It will also support new forms of customer-friendly ticketing such as print-at-home tickets.
During the upgrade it will not be possible to view the availability of, or to sell, Advance tickets because they require mandatory reservations; neither will it be possible for customers to make reservations for other types of ticket. Off-Peak and Anytime fares without seat reservations will continue to be available from all usual retail channels. Timetable information will not be affected.
Please can you ensure all team members and any self-booking clients are aware of this short period where Advance tickets, and seat reservations will not be available.