Actually, they haven't changed parties as yet - just decided to, "Caucus", with the Republicans - has the same effect. Cam Edwards had a segment about it on NRA News last night. Go to
http://www.nranews.com/#/news, click on "Program Archive" near the top, then to, "June 08", on top of the window that opens on the right. Scroll down to, "Greg Costa" an hit that. The segment will play - interesting. The whole site is much better now than it was!