You will need the Write Safeguards permission to perform this action.
Navigate to the person who has the safeguard you are interested in editing and go to the "Safeguards" tab. Locate the safeguard in the table and click on "Edit" at the end of the row. You can also click on the "Type" in that row.
A pop up will appear where you can edit the details of the safeguard. See this article for information regarding the fields.