Once a risk has been successfully managed, residual risks addressed, and there are no secondary risks, the next step according to risk management best practices is to formally close the expired risk and update all relevant project documentation. The PMBOK Guide states:
"Once the risk responses have been implemented, and the risk is no longer a threat or opportunity, the risk should be closed out in the risk register and the results should be documented as part of project records and lessons learned."
- PMBOK Guide, 6th Edition, Section 11.7.3.2
Closing the risk ensures transparency and supports organizational learning through updated project records.
References:
PMBOK Guide, 6th Edition, Section 11.7.3.2
Practice Standard for Project Risk Management, PMI, Section 6.7