The first thing that a risk practitioner should do upon learning that a risk treatment owner has implemented a different control than what was specified in the IT risk action plan is to reassess the risk level associated with the new control. This is because the new control may have a different effect on the likelihood and impact of the risk, and may introduce new risks or modify existing ones. The risk practitioner should evaluate the adequacy and effectiveness of the newcontrol, and compare the residual risk with the risk appetite and tolerance of the organization. The risk practitioner should also communicate the results of the risk reassessment to the relevant stakeholders, and update the risk register and action plan accordingly. The other options are not the first things that a risk practitioner should do, although they may be necessary or appropriate at a later stage. Seeking approval from the control owner is important, but it does not address the potential changes in the risk level or the alignment with the risk management objectives. Updating the action plan in the risk register is a good practice, but it should be done after the risk reassessment and with the consent of the risk owner. Validating that the control has an established testing method is a part of the control assurance process, but it does not provide information on the risk level or the risk response effectiveness. References = Risk and Information Systems Control Study Manual, Chapter 4: Risk Response, page 151.