India, March 9 -- Millions of Americans who rely on Social Security benefits are facing a major change after the Social Security Administration (SSA) rolled out a nationwide overhaul that alters how claims and appointments are handled, replacing the long-standing local-office system with a centralized national model.

The SSA said earlier this year that Social Security beneficiaries will no longer be assisted by personnel from local field offices when arranging appointments beginning March 7.

Instead, appointments and claims will be routed through a national workload management system, meaning cases may be processed by employees anywhere in the country.

SSA has rolled out two new technology platforms across the country: the National App...