Navigate to the The Baseline history page page from the The Branch baselines page or The Apps & tests page.
Find the row with the revision you are interested in, and on the row menu select Save as latest. This entry will be grayed out if the revision already is the latest revision. The information in the selected revision will be cloned, and a new revision will be stored with the current time and date. Any tests now run on this baseline will be compared to the newly cloned baseline.