Registration authorities (RAs) exist for many standards organizations, such as ISO, the Object Management Group, W3C, and others.
The Object Management Group has an additional concept of certified provider, which is deemed an entity permitted to perform some functions on behalf of the registration authority, under specific processes and procedures documented within the standard for such a role.
Frequently, facilitating the implementation of an ISO standard's requirements is best suited, by its nature, to one entity, an RA.
[1] In most cases, there is a formal legal contract in place between the standards body, such as the ISO General Secretariat, and the selected registration authority.
While registration authorities for a particular standard typically do not change, the position is not formally guaranteed and is subject to review and reassignment to a different firm or organization.