I'm not sure I understand the connection between H and C and PRRA, except currently they're both done by the same officer at the same time. But the person's rights on transition are that up to the point where the RAD provisions come into force, the person whose claim is rejected after royal assent will have access to H and C consideration if they wish to apply, and if they are subject to removal from Canada, they will have access to a pre-removal risk assessment.
After the coming into force of the RAD provisions, the persons whose claims had been determined prior to the coming into force would not automatically have access to RAD at that point, but they would continue to have access to pre-removal risk assessment.