Citations saved in RIS format (Research Information Systems citation format) can be imported to EndNote bibliography search tool and saved in the programs default library (.enl). This seems to be pretty much the only way how you can achieve this conversion.
Convert Research Information Systems citation to Endnote library.
We found 3 software records in the database related to .ris to .enl file format conversion.
Microsoft Windows software - convert ris to enl on Windows
Search tool for online bibliographic databases
Convert from ris file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned ris to enl. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert ris to enl on OS X
Application to organize bibliographies
Apple iOS (iPhone, iPad, iPod Touch devices) software - convert ris to enl on iOS
App for iPad used to search in bibliographic databases