There are a couple of main ways to update or edit a Risk/Issue, if you have the necessary permissions.
Anywhere you see a list of Risks, Issues or Action Steps, you can edit certain fields inline (straight from the table). Just hover over a field and if a blue pencil icon appears next to it, you can edit inline! Click the pencil, make the changes you need, and click away to save - it is that easy! See a video at the bottom of this page giving an example of how this works.
Updating Risk RAG Inline (changing Impact/Likelihood)
To update the RAG of a Risk/Issue, which involves changing its Impact and Likelihood scores, click on its RAG triangle on any list of Risks or on its Details Page, and in the resultant popup slide the Impact and Likelihood sliders to the desired settings before clicking save.
Editing through Details Page
To change any part of the Risk/Issue, including Status (if you are a Project Manager, Risk Manager or Admin User), you must click on the title of the Risk/Issue you want to edit, then click the pencil icon on the right of the Title bar and make the changes you want on the Edit form.