To change to the online version of endnote (word 2010-2013) - on the endnote ribbon, open the " Preferences ". and the last tab is Applicaiton. You change to Endnote Online from the dropdown there.
And I tested, the citations in the formatted manuscript do not need to be in the online library. It will fix the ambiguous lettering just find with the online version of endnote and APA 6th.