The Mann Theatre at The Promenade at Westlake closed on December 27, 2011, as discussed in this Dec 23 VC Star article and Dec 22 San Fernando Valley Business Journal article.
This was the last of the Mann theaters. Recently the Mann Theaters at the Janss Marketplace were sold to Regency Theaters and earlier this year the Mann Chinese Theater was sold and now is simply called Chinese Theatre.
The space will be taken over by Cinépolis Luxury Cinemas, which will open a high-end theater with plush seating and waiters. Nice! Sounds like a Muvico competitor! This VIP concept has been in place since 1999 in Mexico and they are quickly expanding into Southern California.
Cinépolis is the 4th largest movie theater chain in the world, which is news to me. Probably because most of their 230 theaters worldwide are in Mexico.