If a journal article (or other reference work) has been retracted, does Endnote indicate this?
I don’t know the convention, but there is no way for Endnote to “recognize” this if it happens in the future.
Details of how Pubmed labels these are http://www.nlm.nih.gov/pubs/factsheets/errata.html. so there are specific fields (see field info about 1/6th way downthis page (search for retract) so I assume it might end up in Endnote’s comment field? I haven’t checked though.