What does it mean to keep social insurance related personnel by agreement?

Hello! "Conserving social insurance relationship by agreement", referred to as "co-insurance", is a security policy adopted by some older workers during the restructuring of state-owned enterprises. That is, employees' social insurance is paid in one lump sum from the original unit to the retirement age, and the labor relationship is preserved. Employees do not need to pay social insurance when they apply for jobs in society, thus reducing the burden on laid-off workers. However, this policy has an age limit. Male employees born before 1957 12 3 1 can enjoy it, while female employees born before 1962 12 3 1 can only enjoy it, and those born after that can only buy out their length of service.