Q: how to add an empty disk partition into an existing partition (El Capitan)

So I already partitioned my internal disk drive into two, one for BOOTCAMP (Windows) and for the Mac OSX Boot drive (El Capitan). I wanted to allocate more space into my Mac OSX Boot drive (El Capitan), so I made a new partition named Untitled, that came from the BOOTCAMP drive. I just wanted to know how to add the Untitled, empty BTW, into my existing El Capitan drive. It looks like this:

The blue highlighted partition is the empty one that i'm trying to add to the Mac OSX Boot drive (the one with 46GB)

Thanks for your help!