Cirrocumulus are a high-level cloud (found at altitudes above 16,000 ft) that, similar to other cumuliform types of clouds, indicate instability. These consist of small amounts of liquid water that are supercooled, meaning they exist in liquid form at temperatures below freezing. Ice crystals are also present, which cause the supercooled drops to freeze and change the cirrocumulus into cirrostratus.
Here is an example of this transition from April 2013 over Seattle. You can still make out some of the individual cloud elements (the cirrocumulus), but overall, they are less defined and becoming more stratified/spread out.
Location: Seattle, Washington
Date: April 2013