The most effective and transparent approach is for the risk manager to collaborate with the project manager to communicate risk levels to stakeholders. According to PMI's PMBOK Guide and Practice Standard for Project Risk Management, communication of risk should be timely, consistent, and include all relevant stakeholders-not only those who are supportive. Risk information must not be withheld or selectively communicated as this could damage trust and the integrity of the risk process.
"Effective risk communication involves collaborating with the project manager and stakeholders to ensure risks are reported honestly and objectively... Failure to communicate risks in a timely and complete manner can lead to stakeholder dissatisfaction and jeopardize project objectives."
- PMBOK Guide, 6th Edition, Section 11.5.2.6 (Project Document Updates: Risk Report, Communications Management) Also, the Practice Standard for Project Risk Management states that risk communication should be performed collaboratively to ensure the right message, context, and tone are used.
References:
PMI PMBOK Guide, 6th Edition, Section 11.5
Practice Standard for Project Risk Management, PMI, Section 6.2