How to cancel the social security card handled by the undergraduate school?

The campus medical insurance card and the social security card of the unit are unified now, but in the school, residents' medical insurance is paid once a year, and the unit is urban workers' medical insurance once a month. After graduating from college, the medical insurance card and medical insurance number remain unchanged, and employees can renew their insurance directly in the unit. At school, you can't cancel. It doesn't matter if you owe money, because the school's medical insurance is residents' medical insurance. If you don't pay, you won't enjoy medical reimbursement and you don't have to pay it back. The medical insurance number and ID number cannot be changed, and the unit will not check your previous arrears. As long as you renew your insurance, you don't have to pay it back.