I've been having this issue with InDesign CC lately, its importing some of my pantone colors as LAB colors. I am able to change a spot to process, but as far as changing the LAB color to a CMYK color, the box is grayed out and is not giving me an option to do it. See screenshot: http://i.imgur.com/J50nmIn.png
Go to the Ink Manager and check it there.
The ink manager is showing just the CMYK, but in the swatches pallet it's still a LAB color
It's because you have a placed file somewhere that has a spot color named PANTONE 370 U. You can choose whether the color will get converted to process or remain spot, but you can't change its name or color definition, unless you delete the links first.
In CS6+ the Pantone spot libraries use the more accurate Lab definitions