In InDesign you can right-click in the swatches panel and select 'Merge Swatches' (among many other things).

In Illustrator there is no right-click menu at all, you have to click the fly-out.

Adding the right-click menu (or even the ability add a keyboard shortcut to things in the fly-out) would be helpful as we get a lot of files with duplicate colors or need to convert odd mixes/incorrect names to true Pantones so our rips will recognize them. We do a lot of merging.

Thank you!