Barnes & Noble (NYSE:BKS) and Microsoft (NASDAQ:MSFT) have reshaped their collaboration in the e-reader space. According to an SEC filing, the two companies have amended an agreement signed in 2012 concerning the bookseller's Nook software. In the amendment, Barnes & Noble's Nook Media subsidiary is to be allowed to discontinue distributing its Windows app in favor of an effort to "cooperate in good faith with Microsoft to transition users to the Microsoft Consumer Reader."

Additionally, the two firms have "agreed to co-branding within the Microsoft Consumer Reader for reading content delivered by NOOK Media," the filing states. 

Microsoft Consumer Reader does not currently exist; according to speculation in the media, it's likely an app that's being developed by the software giant.

The e-reader efforts of Barnes & Noble and Microsoft are intertwined. In May 2012, the latter invested $300 million for a nearly 18% stake in the Nook division.