According to the LyX wiki and other sources I can use
\renamecommand{\abstractname}{Summary}
without an \addto if I remove (or deactivate) the babel package.
The document class is KOMA-script Report.
Under Tools -> Preferences -> Language Settings -> Language I changed
'Default' to 'English' and Language Package to 'None.' When I try to compile
the document for a preview now I get an error: Undefined control sequence.
Missing \begin{document} and the command was never def'd.
What simple thing have I missed here?
TIA,
Rich