Nonconformity = non-fulfilment of a requirement.
When a nonconformity occurs, you need to react:
Take steps to manage and correct what has happened. Deal with the consequenses.
Evaluate the need for action to eliminate the cause of the nonconformity to prevent it from happening again.
Implement necessary steps
Evaluate the effects
Consider to update risk assessments in the organization
If necessary, do adjustments in your routines.
According to SAK10 §10-1 d you need to have "routines for identifying, managing and closing nonconformities, including preventing repetitions of nonconformities with regard to requirements".